af 

5t 


COr  iTISTRY 


UNIV  JFORNIA 


THE  SILICATES 

IN  CHEMISTRY  AND  COMMERCE 


THE  SILICATES 

IN  CHEMISTRY  AND  COMMERCE 


INCLUDING    THE    EXPOSITION    OF    A    HEXITE    AND 

PENTITE  THEORY  AND  OF  A  STEREO-CHEMICAL 

THEORY    OF    GENERAL    APPLICATION 


BY 


DR.  W.  ASCH   AND   DR.  D.  ASCH 


TRANSLATED,  WITH  CRITICAL  NOTES  AND  SOME  ADDITIONS.  BY 

ALFRED   B.  SEARLE 

AUTHOR  OF  "THE  NATURAL  HISTORY  OF  CLAV" 

**  BRITISH  CLAYS,  SHALES  AND  SANDS " 
"CEMENT  CONCRETE  AND  BRICKS"  ETC.  ETC. 


^,  R.  A  R  Y^s> 


COU.LGE    Oi; 

,cnS,TY  OF  CM-tFORNtM 


U  W '  ^ 

'•- 


NEW  YORK 

D.  VAN  NOSTRAND  CO. 

TWENTY-FIVE    PARK    PLACE 

1914 


„. 

* 


CONTENTS 

INTKODUCTION 

PAGE 

The  Chemistry  of  Carbon  and  Silicon         .  .  .  .        .        1 

SECTION  I. 

Historical  Review  of  Existing  Theories  concerning  the  Constitution  of 
the  Aluminosilicates  and  other  Silicates  .  .  3 

The  theories  of  Berzelius,  Smithson,  and  Dobereiner.     The  theories  of 

Wartha,  Haushofer,  Safarik.  Tschermak's  Felspar  Theory.  The  concep- 
tion of  the  acid  nature  of  aluminosilicates  by  Bonsdorff,  Scheerer,  Ber- 
zelius, Bodecker,  Odling,  Wartha,  and  Brauns.  The  acid  nature  of  alumina 
in  aluminosilicates  according  to  Vernadsky  and  the  attempts  made  by 
him  to  devise  a  general  Chemical  System  of  aluminosilicates.  Modern 
theories  of  aluminosilicates,  including  those  of  Rammelsberg,  Groth, 
Clarke,  Tschermak,  Sawtschenko,  Goldschmidt,  BombiccL  Brauns,  Mellor 
and  Holdcroft,  Vernadsky,  Pukall,  Morozewicz  and  Dalkuhara. 

SECTION  II. 
Critical  Examination  of  Existing  Theories  concerning  Alumino-silicates 

Are  the  aluminosilicates  salts  of  the  silicic  acids  ?  Are  the  alumino- 
silicates double  salts  ?  Are  the  aluminosilicates  molecular  combinations  ? 
Are  the  aluminosilicates  isomorphous  mixtures  ?  Are  the  alumino- 
silicates complex  acids  or  the  salts  of  such  acids  ?  The  chemical  nature 
of  the  complex  acids  and  their  salts  as  shown  by  chemical  and  physio- 
chemical  investigations.  Ostwald's  definition  of  double  salts  and  com- 
plexes and  the  behaviour  of  silico-molybdates  and  sulpho-molybdates  in 
aqueous  solutions.  The  course  of  reaction  in  the  formation  of  complex 
acids  according  to  Blomstrand  and  Friedheim.  The  disadvantages  of  Blom- 
strand  and  Friedheim's  theories.  The  facts  for  and  against  the  complex 
nature  of  the  aluminosilicates.  The  results  which  follow  from  the  various 
theories  concerning  aluminosilicates.  Clarke's  formulas  for  alumino- 
silicates. The  constitution  of  Phakelite  according  to  Groth,  Rammels- 
berg, Thugutt,  and  Vernadsky.  The  constitution  of  Potash  Felspar 
according  to  Tschermak,  Groth,  Clarke,  Thugutt,  Rammelsberg,  Wartha, 
Vernadsky,  Zulkowski,  Haushofer  and  Mellor  and  Holdcroft.  The  results 
of  the  foregoing  critical  examination  and  the  possibility  that  the  opposi- 
tion of  some  hypotheses  to  the  complex  nature  of  the  aluminosilicates  is 
only  superficial. 

SECTION  III. 

A  Hypothesis  concerning  the  Bonding  of  the  Atoms  in  Aluminosilicates 
and  Allied  Compounds  .  .  .  ..  .        .30 

Two  new  radicals — Hexite  and  Pentite.  A  structural  chemical  representa- 
tion of  the  complex  aluminosilicic  acids  and  their  anhydrides  based  on 
the  use  of  hexite  and  pentite  radicals  of  silicon  and  aluminium. 


viii  CONTENTS 

PAGE 

The  Consequences  of  the  "Hexite-Pentite  Theory,"  and  the  Facts         .      38 
I.  The  Reactions  during  Double  Decomposition  .  .      38 

Lemberg's  researches. 

II.  The  Genetic  Relationship  between  the  various  Aluminosilicates       40 

The  researches  of  Lemberg,  Thugutt,  and  Friedel.  The  Pseudomor- 
phous  processes.  Table  showing  the  changes  observable  in  alumino- 
silicates  in  nature. 

III.  The  Possibility  of  a  Chemical  System  of  Aluminosilicates  47 

The  Clintonite  group.  The  Mica  group.  The  Scapolite  group.  The 
Orthochlorite  group.  The  Tourmaline  group.  The  Felspars. 

IV.  The  Variable  Chemical  Behaviour  of  part  of  the  Aluminium  in 
Kaolin,  Nepheline,  and  in  the  Epidotes  .  .      51 

The  variable  chemical  behaviour  of  part  of  the  hydroxyl  in  the  Topazes 
and  of  the  aluminium  in  the  Granites. 

V.  The  Minimum  Molecular  Weight  of  Aluminosilicates  .      56 

The  minimum  molecular  weight  of  aluminosilicate  in  connection  with 
Lemberg's  researches.  The  minimum  molecular  weight  in  connection 
with  Thugutt's  work  on  potash,  felspar,  the  mesolites,  and  the  sodalites. 

VI.  The  Constitution  of  Andesite         .  . ,-  .  .      62 

VII.  The  Possibility  of  Isomerism          .  .  .  63 

Basic  Isomerism.  Ring  Isomerism.  Isomerism  in  potash  and  soda 
felspars.  Two  isomeric  sodalites. 

VIII.  Water  of  Crystallisation  and  of  Constitution;  Basic  and  Acid 

Water      .  .  .  .  .      65 

The  structural  formulae  of  the  Zeolites :  Laumontite,  Thomsonite, 
Hydronephelite,  Heulandite,  Epistilbite,  Stilbite,  Faujasite,  Scoleszites, 
Foresite  and  Natrolite,  etc.,  according  to  Clarke,  Friedel,  Mallard, 
Rhine,  Damour,  Sommerfeldt,  van  Bemmelen,  Doelter,  Henry,  and 
others. 

IX.    Prognoses  .  .  .  «  .  73 

Base  Prognoses.  Ring  Prognoses.  The  theoretically  possible  Arden- 
nites.  The  theoretically  possible  Sapphirines.  The  structure  of  How- 
lite,  Avasite,  Milarite,  Ptiolite,  and  Mordennite. 

X.  The  Constitution  of  the  Complexes  of  Molybdenum  and  Tungsten     78 

a-  and  /3-Complexes  of  Molybdenum  and  Tungsten.  Evidence  in  sup- 
port of  the  structural  chemical  representation  of  molybdic  and  tungstic 
complexes.  The  results  of  researches  by  Friedheim  and  his  associates. 
The  action  of  molybdic  acid  on  various  vanadates  and  of  vanadates  on 
molybdates.  The  action  of  molybdic  acid  on  various  phosphates. 
The  action  of  molybdic  acid  on  arsenates.  The  genetic  relationship 
between  the  various  vanadinomolybdates.  The  most  stable  types  of 
vanadinomolybdates  and  aluminosilicates.  The  genetic  relationship 
between  a-  and  /S-phospho-molybdo  complexes.  The  genetic  relation- 
ship between  the  arseno-molybdates.  The  different  behaviour  of  the 
compounds  2  R2O  •  V2O5  •  4  WO3  and  4  R2O  •  3  V2O6  •  12  WO3  to- 
wards acids  in  the  light  of  Friedheim's  and  the  Hexite-Pentite  theories. 
The  constitution  of  "the  Silicotungstates.  The  isomeric  silicotungstic 
acids  and  silicotungstates.  The  dimorphism  of  the  potash  salt  K2O  • 
2  H2O  •  SiO2  •  12  WO 9  •  7  H2O  in  the  light  of  the  Hexite-Pentite  theory. 


CONTENTS  ix 

PAGE 

Systematic    Review  of  a  Series  of  /3-Complexes   of  Molybdenum  and 

Tungsten      .  .  .  .  .  ...      96 

Aluminomolybdates  R2O  •  A12O3  •  10  MoO3.  Borotungstates  2  R2O  • 
B2O3  •  10  WO  8.  Silicotungstates  4  R2O  •  SiO2  •  10  WO3.  Platino- 
molybdates  4  R2O  •  PtO,  •  10  MoO3.  Platinotungstates  4  R2O  •  PtO2  • 
10  WO 3.  Alummomolybdates  3  R2O  -  A12O3  .  12  MoO3.  Chromomolyb- 
dates  3  R2O  •  Cr2O3  •  12  MoO,.  Borotungstates  4  R2O  •  B,,O3.  12  WO3 
Silicomolybrlates  2  R2O  •  SiO,  •  12  MoOs.  Silicomolybdates  4  R20  • 
SiO2  •  12  MoO 3.  Silicotungstates  4  R2O  •  SiO2  •  12  WO8.  Zirkono- 
molybdates  2  R2O  •  ZrO2  •  12  MoO,.  Titanomolybdates  2  R2O  •  TiO2  • 
12  MoO  3.  Phosphotungstates  2  R2O  •  P2O5  •  12  WO3.  lodomolybdates 
5  R2O  •  I2O7  •  12  MoO3.  Phosphomolybdates  R2O*  •  P2O5  •  15  MoO,. 
Manganomolybdates  o  R2O  •  Mn0O3  •  16  MoO3.  Phosphomolybdates 
3  R2O  •  P0O5  •  16  MoO*.  Phosphotungstates  6  R0O  •  P2O5  •  16  WO3. 
Phosphomolybdates  3  R2O  •  P?O5  •  18  MoOE.  Phosphotungstates  6  R26- 
P2O5  •  18  WO3.  Arsenomolybdates  6  R26  •  As2O5  •  18  MoO3.  Phos- 
phomolybdates 7  R2O  •  P2O5  •  20  MoO3.  Phosphotungstates  6  R2O  • 
P2O5  •  20  WO 3.  Arsenomolybdates  3  R2O  •  AsoO5  •  20  MoO3.  Phos- 
phomolybdates 7  RoO  •  P»O,  •  22  WO 3.  Phosphomolybdates  6  R2O  • 
Pj,O8  •  24  MoO  s.  Phosphotungstates  3  R2O  •  P2O5  -  24  WOa. 

XI.  The  Constitution  of  Clays  .  .  ...    102 

The  theoretically  possible  aluminosilicic  acids.  Hydrates  and  An- 
hydrides. Isomeric  aluminosilicic  acids.  Water  of  crystallisation  and 
of  constitution.  The  minerals  of  the  Allophane  group  as  examples  of 
hydro-aluminosilicates.  The  water  of  crystallisation  and  of  constitu- 
tion in  the  minerals  of  the  Allophane  group.  The  maximum  of  water 
of  constitution  in  minerals  of  the  Allophane  group.  Formulation  of  a 
series  of  analyses  of  washed  clays.  The  acid  character  of  the  clays  shown 
by  their  chemical  properties.  The  unitary  nature  of  clays  according  to 
C.  Mene.  The  behaviour  of  clays  towards  concentrated  sulphuric  acid. 
"  Clay  substance."  The  constitution  of  clays  according  to  Forch- 
hammer.  The  value  of  "  rational  analyses  "  according  to  Mellor  and 
Holdcroft,  Seger,  Brongniart,  and  Malaguti.  Definition  of  "  disdyna- 
mtsed  "  and  "  dynamised  "  substances.  Vitrification  of  clays.  Second- 
ary valencies  of  oxygen  in  clays.  Effect  of  heat  on  clay,  according  to 
Rieke,  and  Mellor  and  Holdcroft.  Polymerisation  of  Alumina.  The 
chemical  changes  occurring  in  the  burning  of  clays.  Isomerism  and 
Polymerism  of  Kaolin.  The  H.P.  theory  and  the  Facts.  Pukall's  re- 
searches on  Kaolin.  The  behaviour  of  Pukall's  sodium  s-kaolinates  to- 
wards carbonic  acid  and  towards  hydrochloric  acid.  Mellor  and  Hold- 
croft's  researches  on  Kaolin.  The  melting  point  of  clays  and  other 
aluminosilicates.  Relation  between  Melting  Point  and  Composition 
of  Clays.  Mineralisers.  Plasticity.  A  new  theory  of  plasticity.  The 
Colour  of  Bricks. 

XII.  Ultramarines         .  .  .  <  .        .   .       .    136 

Historical  Review.  A  new  theory  of  the  ultramarines.  Two  kinds  of 
hydroxyls  in  hydro-aluminosilicates  of  the  type  H  12  H  4  (Si  •  Al  • 

Al  •  Si),  viz.  a  and  s-hydroxyls.  The  replaceability  of  hydrogen  in  the 
a-hydroxyls  by  acid  residues.  The  curious  property  of  the  compounds 

Na8  H4  (Si  •  Al  •  Al  •  Si)  discovered  by  Silber.  The  ultramarines  as 
A-  and  2-aluminosilicates.  The  role  of  the  group  S.,O7  in  ultra- 
marines. Sulphonates.  The  Sulphonates  as  Chromophores.  The 
changes  in  the  intensity  of  colour  (Schiitz).  The  relationship  between 
colour  and  constitution  (R.  Nietzki  and  others).  The  Hexite-Pentite 
Theory  of  Ultramarines  and  the  facts.  Theoretically  possible  ultra- 
marines. New  formulse  calculated  from  analyses  of  ultramarines. 
Aluminosilicates  from  which  ultramarine  cannot  be  made.  Ultra- 
marines of  different  colours,  and  their  constitutions.  Isomeric  ultra- 
marines. The  behaviour  of  ultramarines  towards  salt  solutions.  The 
behaviour  of  ultramarines  at  high  temperatures.  The  Sulphonate  groups 

A  2 


:  CONTENTS 

PAGE 

and  the  colour  of  ultramarines.  The  behaviour  of  ultramarine  towards 
acids.  The  maximum  contents  of  base  in  ultramarines.  The  minimum 
molecular  weight  of  ultramarine  compounds.  The  minimum  molecular 
weight  of  "  Ultramarine  blue,"  according  to  Guckelberger.  The  ultra- 
marines as  definite,  single  chemical  compounds.  Analogy  between 
ultramarines  and  sodalites, 

XIII.  A  New  Theory  of  Hydraulic  Binding  Materials  and  particularly 

of  Portland  Cements     .  .  .  .  .  .    153 

Critical  and  Historical  review  of  existing  theories.  Vicat's  theory. 
Fuchs'  theory.  Winkler's  theory.  Feichtinger's  theory.  The  hypo- 
theses respecting  free  lime  in  Portland  Cement.  The  influence  of 
Fuchs'  theory  on  Heldt,  on  Chatoney  and  Rivot,  and  on  the  investiga- 
tions made  in  order  to  ascertain  the  constitution  of  the  Portland  cements. 
The  theories  of  Le  Chatelier,  Newberry  Bros.,  Kosmann,  Jex,  Erd- 
menger,  Hardt,  Schonaich-Carolath,  Schott,  Zsigmondy,  Meyer- 
Mahlstatt,  and  Rohland.  The  microscopical  examination  of  clinker. 
Portland  cements  as  definite,  single  chemical  compounds.  The  chemical 
constitution  of  Portland  cements.  The  role  of  the  s-hydroxyls  in  the 

compound  H20  (Si  •  Al  •  Al  •  Si)  in  the  synthesis  of  Portland  cements. 
Hydro-  and  anhydro-basic  side-chains.  The  course  of  reaction  in  the 
formation  of  Portland  cements  and  the  influence  of  the  time  and  tem- 
perature of  the  burning.  Sintered  and  fused  cements.  The  changes 
which  take  place  during  the  granulation  of  slags  and  the  production  of 
slag-cements.  Lunge's  research  on  granulated  and  non-granulated 
slags.  Allen  and  Shepherd's  criticisms.  The  constitution  of  slags.  A 
new  theory  of  hardening.  The  new  theory  and  the  facts.  The  role  of 
"  soluble  "  silica  in  the  hardening  of  cements.  The  causes  of  hardening 
of  Portland  cements.  Zulkowski's  theory  of  hardening.  The  conse- 
quences of  the  new  theory  of  Portland  cements  and  the  facts.  New 
formulae  calculated  from  analyses  of  Portland  cements.  Stoichiometric 
representation  of  the  absorption  of  water  by  cement.  Regular  increase 
of  water-content  on  hydration  of  cements.  The  results  of  Feichtinger's 
researches  on  certain  hydraulites  :  silicate-water,  calcium  hydroxide 
water,  and  water  of  crystallisation.  Feichtinger's  researches  as  evidence 
for  the  non-existence  of  free  lime  in  Portland  cements.  The  possibility 
of  regenerating  certain  hardened  cements  and  Feichtinger's  researches 
thereon.  Hydration  and  evolution  of  heat.  Ostwald's  thermo-chemical 
investigations  on  cements.  The  transition  of  primary  types  into 
secondary  ones  in  Portland  cements  and  Feichtinger's  researches  thereon. 
The  separation  of  lime  in  hydraulites  in  accordance  with  certain  stoichio- 
metrical  laws.  The  hardening  power  of  hydraulites  after  removal  of 
definite  proportions  of  the  lime.  The  maximum  contents  of  silicate- 
water  and  calcium  hydroxide  water.  The  second  setting  of  previously 
hardened  masses  which  have  been  re-ground.  The  cause  of  "  soluble 
silica  "  in  hydraulites.  The  behaviour  of  hydraulites  towards  strong 
acids.  The  possibility  of  isomerism  in  cements.  Prognoses  of  the  pro- 
portions of  chalk  and  clay  in  the  Taw  mixture.  A  new  solution  of  the 
Sea  water  problem.  The  value  of  cements  which  contain  no  a-hydroxyls, 
especially  for  maritime  work.  Prognoses  of  ultramarine  cements. 

XIV.  A  New  Theory  of  the  Porcelain  Cements  as  used  for  Dental 
Fillings       .  .  .  .  .  ...    19^ 

The  first  porcelain  cement  (Fletcher's).  The  use  of  porcelain  cements 
in  dentistry  (Morgenstern).  The  chemical  composition  of  porcelain 
cements.  The  properties  of  an  ideal  dental  stopping  (Miller).  The 
value  of  a  scientifically-founded  theory  of  porcelain  cements  for  the  pro- 
duction of  dental  stoppings.  Laboratory  tests  on  porcelain  cements. 
The  superiority  of  porcelain  cements  over  ivory  and  natural  dental 
enamel  so  far  as  resistance  to  acids  is  concerned,  and  the  use  of  this  in 
solving  the  problems  of  the  course  of  reaction  in  the  hardening  of  such 
cements.  Critical  review  of  the  various  theories  of  hardening  of  porce- 
lain cements.  The  chief  cause  of  failure  of  porcelain  cements  according 


CONTENTS  xi 

PAGE 

to  Jung  and  Morgenstern.  Kulka's,  Rawitzer  and  Apfelstadt's  theories 
of  hardening.  Are  porcelain  cements  single,  definite  chemical  com- 
pounds ?  The  composition  of  porcelain  cements  as  shown  by  Patent 
Specifications.  A  physio-chemical  theory  of  the  hardening  of  porcelain 
cements.  The  chemical  constitution  of  porcelain  cements.  The  role  of 
the  s-hydrogen  in  hydro-aluminosilicates  in  the^  synthesis  of  porcelain 
cements.  The  difference  between  Portland  and  porcelain  cements. 
The  acido-  and  baso-philism  of  aluminosilicates.  The  acidophilism  of 
the  a-  and  s-hydrogen.  The  different  binding  power  of  fluorine  in  topazes. 
The  acido-  and  baso-philism  of  the  artificial  zeolites  studied  by  Gans. 
The  amphochromatophilism  of  Kaolin  (Hundeshagen).  The  acido-  and 
basophilism  of  kaolin  in  the  production  of  colour  lakes.  The  acido- 
and  baso-philism  of  kaolin  as  deduced  from  the  constitution  of  the  ultra- 
marines. The  physico-chemical  reactions  during  the  hardening  of 
porcelain  cements.  The  A-  and  S-porcelain  cements.  The  course  of 
hydration.  The  course  of  condensation.  The  constitution  of  the 
hardened  A-  and  S-cements.  The  lamellar  hardening  of  dental  cements. 
The  consequences  of  the  theory  and  the  facts.  Calculation  of  formulae 
from  analyses  of  porcelain  cements.  The  absorption  of  water  during 
hardening  must  be  in  stoichiometric  proportions.  Prognoses  of  silicate, 
basic  and  crystallisation  water  in  porcelain  cements.  The  progressive 
hydration  of  porcelain  cements.  Factors  which  affect  the  time  of 
hardening  of  porcelain  cements.  The  high  resistance  of  porcelain 
cements  to  acids  explained  by  the  new  theory  of  hardening.  The  toxic 
action  of  A-cements  on  the  dental  nerve-substance  (pulpa).  The  non- 
separation  of  base  from  A-cements  by  the  cement  acid.  Two  kinds  of 
zinc  phosphate  cements  :  A-  and  S-zinc  phosphate  cements.  Miller's  and 
Black's  physiologico-chemical  experiences  with  A-  and  S-zinc  phosphate 
cements  and  the  consequence  deducible  therefrom.  The  hardened  A- 
cements  as  "  slumbering  volcanoes."  Cause  of  neurotropy  found  in 
alumino-phosphoric  acids  and  Ehrlich's  theory.  Definition  of  neuro- 
tropy. The  facts  in  favour  of  Ehrlich's  theory  of  the  chemical  nature 
of  toxines.  The  chemical  relationship  between  nerve-fibres  and  alumino- 
phosphoric  acids.  Mordanting  animal  fibres.  Siem's  and  Dollken's 
researches  on  aluminous  poisons.  Does  the  acid  reaction  of  an  aqueous 
solution  of  a  metallic  salt  imply  hydrolysis,  i.e.  the  presence  of  a  free 
acid  ?  The  proof  of  non-hydrolysis  of  a  series  of  solutions  with  metallic 
salts  with  an  acid  reaction  by  means  of  conductivity  determinations 
and  spectrum  analysis.  Practical  experiences  of  the  physiologico-chemi- 
cal action  of  A-cements.  Researches  made  with  a  view  to  reducing  the 
poisonous  nature  of  A-porcelain  cements  by  empirical  rules  and  the 
value  of  such  rules.  Pawels'  direct  proof  of  the  poisonous  action  of 
strong  acids  on  the  pulpa  by  means  of  experiments  on  animals.  Tech- 
nical demand  for  improvements  in  A-cements.  Dental  decay  as  the 
cause  of  diseases  of  other  organs.  The  proper  method  of  reducing  the 
poisonous  action  of  the  porcelain  cements  containing  strong  acids. 
Practical  physiologico-chemical  experience  of  S-cements. 

XV.  A  New  Theory  of  Glass,  Glazes,  and  Porcelain         .  .        .    236 

The  chemical  constitution  of  glasses.  Isomerism  in  glasses.  Explanation 
of  cause  of  variable  depression  of  the  zero  point  in  thermometers  made 
of  certain  glasses.  •ycomplexes  as  glasses  and  their  useful  properties. 
The  behaviour  of  glasses  towards  water  and  acids.  Devitrification. 
The  chemical  constitution  of  coloured  glasses.  Witt's  theory.  The 
H.P.  theory  and  the  facts.  Calculation  of  formulae  from  a  series  of 
analyses  of  glasses,  glazes,  and  porcelains. 

XVI.  The  Hexite-Pentite  Theory  as  a  General  Theory   of  Chemical 
Compounds   .  .  .  .  .  .    255 

A.  The  H.P.  Theory  and  the  Composition  of  the  Metal-ammonias  and 

allied  Chemical  Compounds  .  . .  .  .        .    256 

The  disadvantages  of  existing  structural  formulae  of  the  metal-ammonias, 
cyanides,  etc.,  according  to  Kohlschiitter.  Werner's  theory  of  molecular 
compounds. 


xii  CONTENTS 

PAGE 

B.  The  H.P.  Theory  and  "Water  of  Crystallisation"  .  .        .    259 

The  valency  of  oxygen.  The  molecular  weight  of  water.  Water-hexite 
arid  pentite.  Hydro-aluminosilicates.  Hydro-f'errosulphates.  The 
water  of  crystallisation  in  alums.  The  water  of  crystallisation  in  chromo- 
sulphuric  acids. 

C.  The  H.P.  Theory  and  the  Dissociation  Hypothesis  of  Arrhenius      .    266 

D.  The  H.P.  Theory  and  the  Constitution  of  Simple  Acids  .        .    268 

Salts  offthel'acids  H2  -  H4(PO3)fi,  H  •  H4(PO3)S,  and  H12  •  H,(PO3)16. 
Salts  of  the  general  formula  2  Pv"O  •  3  Na2O  •  3  P2O5  •  aq.  Hexite  for- 
mation of  niobic  and  tantalic  acid.  Hexite  and  Pentite  formation  of 
tungstic  acid.  Hexite  and  Pentite  formation  of  the  oxygen  free  acids. 

E.  The  H.P.  Theory  and  the  Carbon  Compounds    .  .  .    271 

Carbon  and  Silicon  Hexites  and  Pentites  devoid  of  oxygen.  Chromium 
hexites. 

F.  The  H.P.  Theory  and  the  Constitution  of  the  Chemical  Atoms : 

The  Archid  Hypothesis          .  .  ..  .  .    273 

The  consequences  of  the  Archid  Hypothesis  and  the  Facts. 

(a)  The  Valencies  of  the  chemical  atoms.     Atoms  with  constant  and 

variable  valencies.     The  valency  of  nitrogen.     The  valency  of 

carbon.     The  minor  valencies  of  carbon. 
(6)  Homologous  series  of  atoms, 
(c)   The  cause  of  radio-activity  and  the  work  of  the  alchemists. 

SECTION  IV. 

The  Conversion  of  the  H.P.  Theory  into  a  Stereo-chemical  Theory  and 
the  Combination  of  the  latter  with  the  Modern  Theory  of  the  Structure 
of  Crystals  ...  .  .281 

(a)  Critical  Review  of  Existing  Stereo-chemical  Theories  .  .    281 

The  Hypotheses  of  van't  Hoff  and  Le  Bel.  The  stereo-chemical  theories 
of  Wernerv-and  Hantzsch,  Schrauf,  Fock,  Groth,  Hunt,  Tutton,  Herz, 
Doelter  and  Vufriik,  Vogt,  van't  Hoft',  and  Becke. 

(6)  The  Modern  Theory  of  the  Structure  of  Crystals  and  the  Possi- 
bility of  Combinations  of  the  same  with  Structural  Chemical 
Theories  .....  .  285 

(c)  Stereo-hexites  and  pentites,  or  a  Stereo-chemical  Theory        .       .    286 

(d)  The  Hexite-Pentite  Law         .  .  .  .  .    289 

(e)  Combination  of  the   Stereo-Hexite-Pentite  Theory  with   Modern 

Theory  of  Structure  of  Crystals        .  .  .    289 

(/)  The  Stereo-Hexite-Pentite  Theory  and  the  Facts  .       .    290 

A.  Dimorphism  and  Polymorphism  and  Hauy's  Law  r  .        .    290 

The  cause  of  dimorphism  in  compounds  with  the  empirical  formula  FeS2. 
Discussion  between  Berthollet  and  Hauy.  Mitscherlich  on  Hauy's  law. 
Geuther's  representation  of  the  dimorphism  of  CaCO3.  Lehmann  on 
Hauy's  law. 

B.  Isomorphism  in  the  Light  of  the  S. H.P.  Theory  .  .        .    294 

The  geometric  constants  of  isomorphous  compounds.  The  isomorphism 
of  minerals  of  the  Felspar  group  and  Tschermak's  theory.  Schuster's 
optical  examination  of  plagioclase.  The  structure  of  albite  and  anorthite 


CONTENTS  xiii 

PAGE 

according  to  Clarke  and  Groth.  Isomorphism  and  the  theories  of  Jannasch 
and  Clarke.  The  structure  of  felspars  in  the  light  of  the  H.P.  theory. 
The  cause  of  isomorphism  in  various  groups  of  silicates  according  to 
Retgers.  The  influence  of  Tschermak's  felspar  theory  on  the  structural 
representation  of  chemical  compounds.  Fock's  mixed  crystals  of  the 
ammonium  salt  (NH4)2O  •  S2O5  •  H  H2O  with  salts  of  the  general  formula 
R"O  •  S2O5  •  i  H2O.  Rammelsberg's  protest  against  the  general  applica- 
tion of  Tschermak's  felspar  theory.  The  theories  of  isomorphous  mixtures 
and  the  facts  opposed  to  it.  Retgers'  attempt  to  produce  mixed  crystals 
from  the  salts  KH2PO4  and  (NH4)H2PO4.  Tammann's  researches  on 
hexa-  penta-  and  the  16-phosphoric  acids.  Isomorphism  of  minerals  of 
the  epidote  group.  Sehultze's  research  on  the  production  of  mixed  crystals 
from  PbMoO4  and  PbCrO4.  Berthollet's  views  and  the  theory  of  isomor- 
phous mixtures.  The  discussion  between  Proust  and  Berthollet  and  the 
result  of  modern  work. 

C.  The  Dependence  of  the  Geometric  Constants  on  the  Side-chains     .    305 

The  influence  of  the  water  of  crystallisation  in  the  form  of  crystals.  The 
crystalline  forms  of  urano-acetate  according  to  Rammelsberg  and  to  the 
S.H.P.  Theory.  Muthmann  and  Becke's  topical  parameter  and  the  dis- 
tance of  molecules  from  each  other  in  a  crystal.  The  influence  of  the  side- 
chains  on  the  crystalline  form  of  benzene  derivatives,  according  to  Groth. 

The  Structural  Formula  of  Benzene  according  to  the  S.H.P.  Theory  .    309 

The  unequal  values  of  the  six  hydrogen  atoms  in  benzene.  Ladenburg's 
views  on  the  disadvantages  of  Kekule"'s  formula  for  benzene.  Glaus' 
formula  for  benzene.  Armstrong's  and  von  Baeyer's  centric  formula  for 
benzene.  The  stability  of  benzene  and  hydrated  benzenes  in  the  light  of 
the  H.P.  theory.  The  relationship  between  the  compounds  of  the  aromatic 
and  aliphatic  series. 

D.  The  Optical  Properties  of  Crystals  and  the  S.H.P.  Theory       .        .    312 

The  relationship  between  crystalline  forms  and  physical  properties. 
Enantiomorphic  crystals.  Abnormal  optical  behaviour  of  the  alums.  The 
cause  of  circular  polarisation  in  some  crystals  according  to  Groth.  The 
production  of  circular  polarisation  by  means  of  sheets  of  mica  (Reusch). 
The  dependence  of  circular  polarisation  on  chemical  constitution.  The 
circular  polarisation  of  organic  compounds  with  asymmetric  carbon  atoms 
according  to  van't  Hoff  and  Le  Bel.  The  optical  behaviour  of  pure  and 
mixed  alums  according  to  Brauns.  Sohncke's  explanation  of  the  cause  of 
circular  polarisation.  The  cause  of  circular  polarisation  in  the  light  of  the 
S.H.P.  Theory. 

E.  The  Dependence  of  the  Geometrical  Constants  on  the  Temperature    316 

Formation  of  calcite  from  aragonite,  according  to  Rose  and  Klein.  The 
change  in  crystalline  form  on  increase  of  temperature,  according  to  Leh- 
mann. 

F.  Molecular  Volumes  and  the  S.H.P.  Theory      .  .    317 

Summary  and  Conclusions      .  ...  \  »         .          318 

The  H.P.  Theory  and  its  critics.  The  value  of  the  H.P.  Theory.  The 
value  of  the  S.H.P.  Theory.  The  aim  of  Science. 

Bibliography  of  references  mentioned  in  text          .  .  .  .        .    328 

Appendix          .  .  .  .  .         .      .    340 

Formulae  and  Analyses  .  ;  v  .         .      .    341 

Formulse  calculated  from  Lemberg's  experiments.  Calculation  of  Formu- 
lae of  the  Topazes.  Calculation  of  Formulae  of  the  Epidotes.  Calculation  of 


xiv  CONTENTS 

FAGE 

Formulae  of  the  Granites.  Calculation  of  Formulae  of  the  Mesolites.  Cal- 
culation of  Formulae  of  the  Clintonites.  Calculation  of  Formulae  of  the 
Micas.  Calculation  of  Formulae  of  the  Scapolites.  Calculation  of  For- 
mulae of  the  Orthochlorites.  Calculation  of  Formulae  of  the  Tourmalines. 
Calculation  of  Formulae  of  the  Felspars.  Calculation  of  Formulae  of  Clays. 
Behaviour  of  a  Series  of  Dried  Clays  towards  Sulphuric  acid  (Bischof). 
Calculation  of  Formulae  from  analyses  of  Ultramarines.  Calculation  of 
Formulae  from  analyses  of  Portland  cements. 

Bibliography  of  references  in  Appendix         .  .  .  .  437 


PREFACE 

IN  the  year  1903,  the  Faculty  of  Philosophy  in  the  University  of 
Gottingen  proposed  the  following  thesis  in  connection  with  the 
Benek  Bequest : 

A  critical  examination,  based  on  experimental  evidence,  is  to  be  made 
of  such  chemical  compounds  as  cannot  be  satisfactorily  explained  by  the 
usual  means.  This  examination  should  also  take  into  special  consider- 
ation the  extent  to  which  the  introduction  of  molecular  additions  is  of 
importance  in  the  formation  of  such  compounds,  and  whether  it  is  possible 
to  devise  a  complete  systematic  arrangement  of  such  compounds. 

Under  the  motto  : 

"  HdvTct  (0eo?)  fji€Tp(t)  Kai  apiOfjLw  KOI  (rraOjuLw  &eTa£e  " 

the  authors  submitted  a  thesis  which  forms  part  of  the  present  volume, 
viz.  pp.  1  to  102  and  the  Appendix.  The  solution  of  the  problem  was 
admittedly  incomplete,  inasmuch  as  only  a  single  branch  of  the  subject 
— the  silicates — was  taken  into  consideration.  For  this  reason  the 
Faculty  did  not  grant  the  first  prize  to  this  thesis,  but  readily  granted 
the  second  prize  "  in  recognition  of  fruitful  labours  leading  to  a  single 
theory  covering  a  very  important  group  of  complex  compounds." 

In  this  way  an  established  theory — the  Hexite-Pentite  Theory — 
was  devised  for  one  highly  important  group  of  complex  compounds — 
the  silicates. 

With  this  theory  in  mind,  it  was  only  natural  to  apply  it  to  a  series 
of  silicates  of  technical  and  commercial  value,  such  as  the  ultramarines, 
Portland,  slag,  dental  and  other  siliceous  cements,  glass,  glazes,  porce- 
lain, etc.,  in  order,  if  possible,  to  elucidate  their  constitution.  This 
has  been  effected  since  the  original  thesis  was  first  written,  and  the 
results  are  published  in  the  following  pages. 

Commencing  with  the  assumption  that  Nature  has  formed  all  sub- 
stances in  accordance  with  monistic  laws,  the  Hexite-Pentite  Theory 
has  also  been  applied  to  the  study  of  the  structure  of  other  complexes 
as  well  as  to  that  of  solutions  of  the  simpler  acids,  etc.,  and  it  has  also 
been  employed,  in  connection  with  the  constitution  of  organic  com- 
pounds, to  form  a  bridge  between  organic  and  inorganic  chemistry. 

XV 


xvi  PREFACE 

In  order  to  take  into  consideration  the  positions  which  atoms  occupy 
in  space  (a  factor  which  is  omitted  from  most  theories  of  chemical 
structure)  the  Hexite-Pentite  Theory  has  also  been  developed,  in 
combination  with  the  modern  theory  of  the  structure  of  crystals,  into 
a  stereo-chemical  theory. 

The  German  edition  of  this  work  was  published  late  in  1911,  but  for 
some  unexplained  reason  almost  every  reviewer  of  that  edition  failed 
to  appreciate  the  advantages  which  may  be  derived  from  this  theory, 
and  with  a  few  exceptions  they  have  overlooked  the  fact  that  the 
Hexite-Pentite  Theory — as  distinct  from  older  ones — is  concerned 
especially  with  inorganic  chemistry,  and  that  it  has  the  following 
characteristics  : 

The  Hexite-Pentite  Theory  is  a  general  and  unitary  theory  ;  it  is 
based  on  a  single  truth — i.e.  on  a  natural  law  found  by  inductive 
reasoning  ;  it  leads  par  excellence  to  prognoses,  and  therefore  permits 
of  deductive  reasoning — the  combination  being  a  clear  sign  of  a  true 
theory — and  it  is,  in  addition,  based  on  the  methods  of  the  most 
famous  classical  chemists.  Moreover,  it  comprehends  the  best  of  the 
existing  theories  or  explains  their  deficiencies,  and  is,  above  all,  a 
definitely  stereo-chemical  theory. 

To  enter  into  a  complete  reply  to  the  various  critics  would  occupy 
too  much  space  in  the  present  volume,  and  as  the  publication  of  the 
present  edition  has  occupied  more  than  a  year  on  account  of  the 
additional  matter  required — much  of  which  is  due  to  the  kind  sug- 
gestions of  the  translator — the  authors  have  decided  to  publish  the 
greater  part  of  their  reply  to  critics  in  a  separate  volume  to  be  issued 
shortly  under  the  title  "  The  Structure  of  Matter."  At  the  same  time  it 
will  be  noted  that  the  chief  criticisms  have  been  met  in  the  present 
edition,  though  the  following  are  conveniently  noted  in  the  Preface 
rather  than  in  the  text. 

A  number  of  critics  adopt  the  remarkable  view  that  the  compre- 
hensiveness and  unitary  nature  of  the  Hexite-Pentite  Theory  are  a 
disadvantage !  This  is  specially  the  case  with  C.  H.  Desch736, 
Allen  and  Shepherd737,  C.  Doelter  ("  Handb.  d.  Mineralchemie  ").  Yet 
comprehensiveness  and  unitary  nature  are  essential  characteristics  of 
any  general  theory.  No  less  an  authority  than  Berthollet  has  declared 
that  the  advantage  of  a  general  over  a  special  theory  is  that  the  former 
has  certain  characteristics,  which  are  precisely  the  ones  possessed  by 
the  Hexite-Pentite  Theory.  In  Gmellin-Kraut's  "  Handb  uch  "  and  other 
classical  text-books  it  is  admitted  that  the  object  of  investigation  is 
to  produce  a  complete  theory  of  chemistry  from  which  all  natural  laws 
affecting  chemical  reactions  can  be  predicted  or  explained.  In  short, 


PREFACE 


xvn 


the  comprehensiveness  of  the  Hexite-Pentite  Theory  is  a  positive 
advantage  and  an  indication  of  its  truth. 

The  earliest  opponents  to  a  unitary  nature  or  monism  in  chemistry 
were  the  French  investigators  Laurent  and  Gerhardt.  Mendelejeff  and 
his  associates,  on  the  contrary,  are  in  favour  of  a  monistic  theory. 
Blomstrand,  Ostwald,  Nernst,  Markownikoff  and  many  other  well- 
known  chemists  have  often  pointed  out  the  fallacy  of  the  conception 
of  the  existence  of  molecular  compounds,  and  these  scientists  are 
therefore  in  favour  of  a  unitary  view.  One  of  the  reasons  why  a  portion 
of  the  present  work  was  granted  a  prize  by  the  Faculty  of  the  Univer- 
sity of  Gottingen  was  that  in  it  the  investigation  leads  to  a  unitary 
conception  of  the  silicates. 

One  of  the  most  valuable  features  of  the  Hexite-Pentite  Theory  is 
that  it  effectively  disposes  of  the  necessity  for  any  dualistic  conception 
of  matter. 

The  classification  of  matter  into  chemical  compounds  and  the  so- 
called  isomorphous  mixtures  or  solid  solutions,  as  is  so  commonly  done 
at  the  present  time,  leads  to  the  conclusion  that  there  are  some  excep- 
tions to  natural  laws.  Yet  when  an  exception  is  found  to  a  natural 
law  this  is  only  an  indication  that  the  terms  in  which  the  law  is  ex- 
pressed must  be  altered  so  that  it  may  include  the  apparent  exception. 
Where  this  cannot  be  done  the  "  law  "  must  be  regarded  as  imperfectly 
understood.  As  Spinoza  has  remarked,  "  No  sane  man  will  believe 
that  Nature  is  limited  in  her  powers  and  that  natural  laws  are  of  limited 
and  not  of  general  application."  The  correctness  of  Spinoza's  teaching 
is  clearly  shown  by  the  small  results  which  have  been  obtained  from 
the  application  of  the  dualistic  or  pluralistic  theory  of  matter,  i.e.  by 
regarding  certain  complex  compounds  as  mixtures.  Thus,  W.  J. 
Miiller  and  J.  Konigsberger779,  in  studying  the  work  of  Day  and  his 
associates  in  Washington  and  of  Doelter  in  Vienna,  point  out  that 
notwithstanding  the  skill  and  expense  involved,  "  the  results  of  these 
investigations  do  not  appear  to  be  commensurate  with  the  labour 
involved."  Miiller  and  Konigsberger  attribute  this  to  the  absence  of 
analogy  between  the  materials  investigated  and  those  used  in  other 
branches  of  chemistry,  but  the  Hexite-Pentite  Theory  shows  that  there 
is  an  abundance  of  analogies,  and  that  the  true  reason  for  the  paucity 
of  results  of  theoretical  value  from  the  Washington  and  Vienna  Insti- 
tutes is  to  be  found  in  the  erroneous  pluralistic  view  of  matter  which 
is  held  by  those  in  charge. 

The  constitution  of  Portland  cement  has  been  the  subject  of  investi- 
gation for  nearly  a  century,  without  any  definitely  satisfactory  result. 
This  is  due  to  precisely  the  same  cause — the  persistent  maintenance 


xviii  PREFACE 

of  a  pluralistic  or  mixture  theory  and  the  neglect  or  repression  of  all 
information  or  suggestions  to  the  contrary.  The  attitude  of  many 
supporters  of  the  mixture  theories  of  Portland  cements  is  far  from 
scientific,  and  notwithstanding  the  abundance  of  proof  of  a  chemical 
nature  in  favour  of  the  Hexite-Pentite  Theory,  those  in  favour  of  a 
pluralistic  conception  of  chemical  substances  still  pin  their  faith  to  the 
very  slender  microscopical  evidence  on  which  their  theories  are  based. 

One  extraordinary  "  result  "  of  following  out  the  mixture  theory  in 
the  case  of  Portland  cement  is  in  the  experience  of  two  French  engineers 
— Chatony  and  Rivot  (see  p.  156  in  the  text) — at  whose  instance 
extensive  maritime  works  were  constructed.  The  panic  amongst 
French  and  other  constructional  engineers  which  resulted  from  the 
destruction  of  these  structures  can  better  be  imagined  than  described  ! 

The  pluralistic  conception  of  chemical  substances  has  also  been  the 
cause  of  a  number  of  serious  accidents  and  bad  results  in  medical 
chemistry.  Thus,  in  the  opinion  of  the  authors,  the  pathology  of  many 
diseases  such  as  diabetes,  cancer,  tuberculosis,  etc.,  must  remain  very 
incomplete,  and  the  nature  and  causes  of  these  complaints  must  be 
completely  misunderstood,  so  long  as  the  pluralistic  conception  of 
matter  is  maintained.  An  interesting  example  of  this  is  found  in  the 
toxic  action  of  certain  dental  stoppings  which  are  fully  described  in 
the  following  pages.  So  firmly  has  the  mixture  theory  been  held  that 
the  opposition  to  these  toxic  cements  was  almost  devoid  of  results,  and 
this  theory  still  exerts  a  considerable  amount  of  influence,  notwith- 
standing the  fact  that  the  authors  have  not  merely  shown  the  causes 
of  the  toxic  action,  but  the  way  to  prevent  it,  and  have  placed  perfectly 
satisfactory  and  non-poisonous  dental  cements,  made  in  accordance 
with  the  Hexite-Pentite  Theory,  on  the  market.  The  continued 
maintenance  of  the  pluralistic  conception  of  matter  in  medicine 
is,  therefore,  even  more  dangerous  than  it  is  in  industry. 

Among  the  various  critics,  it  is  pleasing  to  turn  from  those  who  have 
reviewed  the  first  edition  of  this  book  in  a  careless  or  partial  manner 
to  greater  scientists  like  Wilhelm  Ostwald780,  who  states,  "  The 
authors  commenced  with  an  explanation  of  the  constitution  of  the 
clays  and  allied  substances,  but  passed  on  from  one  branch  of  chemistry 
to  another  until  they  have  eventually  been  able  to  illuminate  an 
astonishingly  large  number  of  different  facts,  all  of  which  are  regarded 
from  the  same  point  of  view."  That  so  able  a  chemist  as  Ostwald  should 
describe  the  present  work  in  such  glowing  terms  is  particularly  gratify- 
ing to  the  authors,  more  especially  as  Ostwald  had  the  opportunity,  as 
a  student  of  Lemberg's,  of  knowing  the  remarkable  pains  which 
Lemberg  took  in  the  prosecution  of  his  investigations — studies  which 


PREFACE 


xix 


have  proved  invaluable  as  a  source  of  experimental  evidence  with 
which  the  Hexite-Pentite  Theory  is  in  complete  agreement.  Ostwald 
even  goes  so  far  as  to  state  that  "  as  an  observer  for  many  years  of  the 
production  and  development  of  many  scientific  theories  and  works  I 
cannot  avoid  declaring  the  present  one  as  most  unusual.  Let  us  give 
a  hearty  welcome  to  these  young  and  energetic  investigators  and  assure 
them  that  the  further  results  of  their  work  will  be  watched  with  the 
greatest  interest." 

In  this  connection  it  is  interesting  to  recall  the  regret  which  Landolt 
expressed  that  his  friend  Kekule  did  not  live  long  enough  to  see  this 
new  triumph  of  his  Benzene  Theory,  for  the  Hexite-Pentite  Theory 
may  be  very  definitely  regarded  as  an  extension  and  development  of 
the  Dalton-Kekule  teaching.  In  a  letter,  Landolt  also  expressed  his 
definite  opinion  that,  sooner  or  later,  the  Hexite-Pentite  Theory  must 
be  taken  up  by  chemists  in  every  branch  of  the  subject.  The  remark- 
able results  which  followed  the  synthesis  of  various  scents,  anaesthetics, 
dyes,  etc.— all  of  which  are  primarily  due  to  the  Kekule  Theory — are 
strong  evidence  in  favour  of  the  Hexite-Pentite  Theory,  for  Kekule's 
theory  is  essentially  a  part  of  the  Hexite-Pentite  Theory. 

Ehrlich's  Side-chain  Theory  is,  in  a  similar  manner,  another  part 
of  the  Hexite-Pentite  Theory,  and  the  enormous  value  of  Ehrlich's 
theory  in  physiological  chemistry  is  already  recognised  by  specialists 
in  this  subject.  . 

It  is  also  interesting  to  observe  that  the  facts  which  have  led  to  the 
Guldberg-Waage  Theory  are  also  direct  consequences  of  the  Hexite- 
Pentite  Theory. 

Even  Newton's  law  of  gravitation  has  an  interesting  connection 
with  the  Hexite-Pentite  Theory. 

The  subject  of  colloids,  which  is  attracting  a  large  amount  of 
attention  at  the  present  time,  is  exceptionally  well  illuminated  by  the 
Hexite-Pentite  Theory,  and  the  authors  had  intended  to  include  a 
considerable  amount  of  information  on  this  subject  in  the  present  work. 
The  amount  of  space  occupied  would  be  so  great  as  to  make  the  present 
volume  inconveniently  large,  however,  and  would  so  seriously  delay 
its  publication  that  this  subject  must  be  dealt  with  in  a  subsequent 
volume.  The  reader's  attention  is,  however,  called  to  the  subjects  of 
cements  and  coloured  glasses — discussed  somewhat  fully  in  the  present 
volume — for  hitherto  the  constitution  of  these  has  usually  been  ex- 
plained in  terms  of  colloids.  Such  an  explanation  is  highly  individual- 
istic and  cannot  be  applied  to  cements  or  glasses  as  a  whole,  so  that 
it  cannot  be  regarded  as  a  really  scientific  hypothesis.  By  means  of 
the  Hexite-Pentite  Theory,  on  the  contrary,  the  cause  of  the  colour  of 


xx  PREFACE 

certain  glasses  is  explained  in  a  manner  precisely  analogous  to  that  in 
certain  coloured  organic  compounds,  wherein  the  colour  is  known  to 
be  due  to  the  arrangement  of  the  atoms. 

In  preparing  this  English  edition,  the  authors  have  had  the  inestim- 
able advantage  of  the  assistance  of  a  well-known  authority  on  clays 
and  other  silicates,  and  they  hereby  wish  to  express  their  indebtedness 
to  him,  not  only  for  the  manner  in  which  he  has  executed  the  transla- 
tion, but  also  for  his  kindness  in  making  numerous  and  valuable 
suggestions  and  criticisms  and  for  the  various  additions  (printed  in 
smaller  type  for  their  better  distinction)  due  to  his  special  knowledge 
of  the  subject. 

THE   AUTHORS. 

July,  1913. 


THE 

SILICATES. 


Introduction 
The  Chemistry  of  Carbon  and  Silicon 

THE  remark  has  frequently  been  made  that,  whilst  the  study  of 
carbon  compounds  has  reached  a  high  state  of  development, 
comparatively  little  attention  has  been  paid  to  that  of  other  elements. 
A  large  number  of  chemists  are  engaged  in  studying  the  chemistry  of 
carbon  because  the  methods  of  investigation  have  been  worked  out 
more  thoroughly  than  those  for  other  elements  ;  because  the  inter- 
pretation of  the  results  is  clearer,  and  because  many  carbon  com- 
pounds, such  as  the  organic  dyestufTs  and  more  recently  the  artificial 
scents,  have  proved  to  be  of  enormous  technical  value. 

The  majority  of  chemical  theories  put  forward  in  recent  years  are 
based  on  the  characteristics  of  carbon  compounds  and  are  modified, 
abandoned,  or  again  become  generally  recognised,  without  the  chemis- 
try of  other  elements  having  any  appreciable  influence  upon  them. 
There  can  be  little  doubt  that  if  the  study  of  other  elements  had 
reached  as  high  a  state  of  development  as  that  of  carbon,  not  a  few 
facts  would  have  been  discovered  which  would  lead  to  other  constitu- 
tional formulae  and  to  fresh  hypotheses  and  theories  ;  it  is,  indeed, 
probable  that  at  least  as  many  new  laws  would  be  formulated  as  have 
resulted  from  the  widespread  investigation  of  the  chemistry  of  carbon. 
These  additional  laws  and  generalisations  should  be  of  even  greater 
value,  inasmuch  as  they  would  be  based  upon  a  wider  knowledge. 

Many  industries  should  derive  considerable  benefit  from  the  results 
of  a  more  thorough  study  of  inorganic  chemistry,  and  new  products — 
or  even  new  industries — would  probably  result.  The  carbide  industry 
and  that  of  the  rare  earths  owe  their  existence  to  an  increased  study 
of  this  branch  of  chemistry.  Other  industries  such  as  those  concerned 
in  the  production  of  artificial  gems,  inorganic  colours,  the  manu- 
facture or  employment  of  cement,  clay,  ultramarine,  glass,  etc.  are 
capable  of  extensive  development  through  the  application  of  scientific 
investigation  to  the  materials  used  in  them. 

Whilst  carbon  has  a  special  interest  on  account  of  its  being  the 


2  INTRODUCTION 

essential  constituent  of  all  organic  substances,  its  analogue,  silicon, 
should  be  no  less  interesting  as  it  forms  the  chief  material  in  the  earth's 
crust.  It  probably  plays  a  far  more  important  part  in  the  natural 
processes  of  the  inorganic  world  than  carbon  does  in  the  realm  of 
organic  substances.  A  moment's  thought  will  show  the  immense 
variety  of  chemical  reactions  and  the  enormous  scale  on  which  they 
occur  in  the  upper  layers  of  our  planet.  The  form  of  the  earth's 
surface,  the  character  of  the  mountain  ranges,  volcanic  eruptions  and 
the  phenomena  of  solution  and  decomposition  are  all  related  to  such 
characteristics  of  the  widely  distributed  aluminosilicates  as  their 
hardness,  fusibility,  heat-conductivity,  resistance  to  pressure,  etc. 
These  characteristics  are  closely  related  to  the  composition  and  the 
chemical  nature  of  the  elements  concerned,  particularly  silicon.  How 
great  an  interest  a  knowledge  of  the  structure  of  these  compounds 
possesses,  is  shown  by  the  manner  in  which  mineralogists  and  chemists 
study  the  crystallographic,  physical  and  chemical  properties  of  rocks 
and  by  the  great  variety  of  theories  which  have  been  formulated  in 
order  to  give  some  idea  of  the  constitution  of  these  remarkable  com- 
pounds. 

In  spite  of  great  intellectual  effort  and  innumerable  experiments — 
only  a  small  proportion  of  which  have  been  published — which  have 
been  made  to  draw  this  subject  from  its  obscurity,  little  progress  has 
been  made,  and  the  silicon  compounds,  in  spite  of  the  fact  that  they 
occur  in  enormous  quantities  and  are  most  widely  distributed,  must 
be  included  amongst  those  substances  of  whose  constitution  very 
little  is  known. 

For  this  reason  it  is  thought  that  a  fresh  attempt  to  illuminate 
this  subject  by  investigating  it  in  a  purely  experimental  manner,  as 
distinct  from  the  more  theoretical  considerations  of  other  scientists, 
may  not  be  without  value. 


HISTORICAL  SURVEY   OF  EXISTING  THEORIES 


Section  I 

Historical  Survey  of  the  various  Theories  regarding  the  Constitution 
of  the  Aluminosilicates  and  other  Silicon  Compounds 

THE  scientific  study  of  the  constitution  of  the  silicates  commenced 
in  the  first  decade  of  the  nineteenth  century  when  Berzelius1* 
Smithson2  and  Dobereiner3  simultaneously  (1811)  regarded  the 
silicates  as  salts  of  silicic  acid  or  silica.  Previous  to  this,  the  role  played 
by  silica  was,  in  spite  of  the  researches  by  Bergemann,  Klaproth, 
etc.,  far  from  clearly  understood.  The  silicates  were  regarded  as 
complex  mixtures  of  various  oxides  and  as  peculiar  substances  quite 
distinct  from  other  salts.  Very  few  suggestions  as  to  their  true  character 
can  be  found  in  the  earlier  literature ;  they  remained  outside  the  general 
development  of  scientific  knowledge,  as  Tachenius — who  regarded  the 
silicates  as  salts  of  silicic  acid — endeavoured  to  show  in  the  seventeenth 
century.4 

Although  the  suggestion  that  the  silicates  are  salts  of  silicic  acid  or 
silica  was  made  simultaneously  and  independently  by  Berzelius, 
Smithson  and  Dobereiner,  as  already  mentioned,  the  chief  credit 
must  be  given  to  Berzelius ;  Smithson  contented  himself  with  stating 
that  minerals  do  not  differ  from  artificially  prepared  compounds, 
and  that  the  composition  of  the  silicates  can  only  be  understood  by 
regarding  them  as  salts,  and  quartz  as  an  acid. 

Dobereiner5  worked  on  purely  speculative  lines,  and  argued  that 
as  silica  forms  salts  with  bases,  the  oxide  of  silicon,  Si02,  should  be 
termed  "  silicic  acid."  f 

Berzelius  expressed  himself  much  less  decidedly,  though  his  meaning 
was  equally  clear.6  He  stated  that  when  two  oxides  combined,  one 
must  be  regarded  as  electro-negative,  and  suggested  that  the  nomen- 
clature of  such  oxides  could  be  distinguished  from  that  of  the  salts. 
Several  years  later  he  classified  silica  compounds  into  bi-silicates,  tri- 
silicates,  etc.  according  to  the  proportion  of  oxygen  in  the  silica  and 
the  base,  and  made  some  very  clear  suggestions  regarding  the  formation 

*  References  to  authorities  are  given  in  the  Bibliography  at  the  end  of  this  volume. 

f  The  term  suggested  by  Dobereiner,  viz.  "  Kieselsaure/'  is  that  used  in 
Germany  at  the  present  day,  there  being  no  exact  equivalent  in  German  to  the  English 
word  "  silica."  The  word  "  Kieselsaure  "  thus  represents  both  "  silica  "  and  "  silicic 
acid,"  the  latter  term  expressing  its  meaning  exactly,  though  seldom  used  excpet  where 
the  acid  nature  of  the  substance  is  specially  under  consideration. — A.  B.  S. 


4          HISTORICAL  SURVEY  OF  EXISTING  THEORIES 

of  the  complicated  salts  of  silica.  At  that  time  he  was  so  convinced  of 
the  acid  nature  of  silica  that  he  believed  that  no  mineralogist 
acquainted  with  the  chemistry  of  the  period  could  have  the  slightest 
doubt  that  silica  was  a  true  acid.  He  maintained — as  Smithson  had 
done  before  him — that  double  salts  existed  in  silicates  containing 
A1203  and  Fe203,  and  pointed  out  the  analogous  nature  of  the  alums 
in  which  silica  is  replaced  by  sulphuric  acid.  He  also  regarded  the 
spinels  as  salts  in  which  A12O3  plays  the  part  of  an  acid.  These  sug- 
gestions were  at  once  accepted  by  scientists. 

By  great  industry,  Berzelius  largely  extended  our  knowledge 
of  silicates.  The  discovery  of  isomorphism  by  Mitscherlich  and  the 
investigations  of  Bonsdorff  and  Rose — two  pupils  of  Berzelius — con- 
firmed their  master's  theories  and  made  it  possible  to  provide  simple 
formulae  for  a  number  of  silicates. 

Through  the  use  of  a  formula — which  for  silica  was  written  as 
Si03,  Si02,  or  SiO — a  great  simplification  occurred,  though  for  the 
silicates  as  a  whole  the  expression  of  the  results  of  chemical  analyses 
by  formulae  did  not  fulfil  expectations.7 

In  1846  Laurent8  suggested  that  the  silicates  are  not  salts  of  a 
single,  but  of  several  silicates.  He  had  proved  the  existence  of  several 
tungstic  acids  and  presumed  the  existence  of  several  silicic  acids  of 
different  chemical  compositions  analogous  to  ortho-  and  meta-phos- 
phoric  acid.  This  hypothesis  was  accepted  by  scientists  as  soon  as  the 
value  of  the  "  Type  theory  "  had  become  generally  recognised.  Be- 
tween 1855  and  1865  it  was  in  great  favour,  and  it  is  still  held  by  some 
chemists.  About  the  time  mentioned,  Fremy's  work  on  tin-acids  was 
published,  and  from  this  arose  the  idea  of  poly-silicic  acids  and  anhy- 
drides, which  was  readily  adopted.  This  hypothesis  has  been  pub- 
lished at  various  times  and  from  various  points  of  view  by  Fremy9,  St. 
Hunt10,  and  Wurtz11,  its  clearest  and  most  accurate  form  being  due 
to  Wurtz.  Various  modifications  of  it  have  been  used  in  theoretical 
investigations  by  several  scientific  writers  with  greater  or  less  effect, 
and  there  is  in  existence  a  long  series  of  treatises,  each  more  or  less 
independent  of  the  others,  forming  complex  combinations  of  old  and 
new  work,  by  Woltzien12,  Golowkinski13,  Odling14,  Streng15,  Lawrow16, 
Schiff17,  Bodecker18,  Stadeler19,  and  others.  The  chief  result  of  all 
these  researches  is  to  indicate  that  the  theories  put  forward  do  not 
de  facto  suffice  to  render  the  constitution  of  the  silicates  clear.  So 
far  as  they  are  concerned,  the  problem  remains  unsolved  in  spite  of 
the  large  amount  of  work  done  in  connection  with  it. 

A  great  advance  was  made  by  Damours20,  who  was  the  first  to 
suggest  that  the  water  in  many  silicates  is  of  the  nature  of  "  water  of 
constitution,"  i.e.  it  is  an  integral  ingredient  of  the  salt  (silicate) 
itself.  The  importance  of  this  observation  was  pointed  out  by  Lau- 
rent21, Bodecker22,  and  Rammelsberg23,  and  its  application  has  greatly 
increased  the  significance  of  the  formulae  of  many  silicates.  More 
recently,  Clarke24  has  endeavoured  to  explain  the  behaviour  of  a 


HISTORICAL   SURVEY  OF  EXISTING  THEORIES          5 

series  of  hydrous  aluminosilicates — the  zeolites — at  high  temperatures 
by  means  of  structural  formulae. 

Many  silicate  formulae  have  been  further  simplified  by  the  employ- 
ment of  microscopical  analysis.25 

There  still  remained,  however,  a  very  large  number  of  silicates 
whose  constitution  cannot  be  ascertained  by  means  of  the  numerous 
investigations  and  exact  analytical  methods  previously  mentioned. 

This  state  of  affairs  naturally  led  to  further  attempts  to  ascertain 
the  constitution  of  the  silicates,  and  numerous  new  theories  were 
formulated.  Thus,  Wartha26,  Haushofer27,  and  Safarik28  endeavoured 
in  1873-4  to  explain  the  chemical  nature  of  the  silicates  by  means  of 
structural  formulae .  These  attempts,  which  were  based  on  theories  of 
the  structure  of  carbon  compounds,  did  not  lead  to  any  definite  result 
and  had  no  appreciable  influence  on  the  development  of  theories 
relating  to  silicates. 

The  felspar- theory  published  by  Tschermak29  in  the  "  Transactions 
of  the  Vienna  Academy,"  in  1865,  on  the  contrary,  was  of  great  im- 
portance, but  was  only  accepted  by  scientists  after  it  had  been  dis- 
cussed for  several  years.*  This  theory,  which  assumes  that  some  of  the 
felspars  are  formed  by  the  mixture  of  two  substances — albite  and 
anorthite — is  well  supported  by  a  large  number  of  analyses,  and  was 
undoubtedly  of  great  value  at  the  time  it  was  introduced.  It  not 
only  facilitated  the  systematisation  of  a  large  number  of  analyses, 
but  explained  the  relationship  between  certain  physical  characters 
and  the  chemical  composition  of  several  silicates. 

In  Tschermak's  theory  the  purely  chemical  functions  of  the 
silicates  are  not  considered ;  this  is  its  great  weakness,  and  for  this 
reason  this  theory  was  only  accepted  by  scientists  for  want  of  a  better 
interpretation  of  the  results  of  innumerable  analyses  of  felspars.  This 
difficulty  existed  until  quite  recently,  for  in  Mineralogy  there  are  a 
number  of  similar  theories  in  which  the  chemical  characteristics  of  the 
compounds  concerned  are  entirely  disregarded,  as  in  the  ordinary 
theories  of  the  chemical  nature  of  Scapolite30,  Mica31'  32,  Tourma- 
line33, etc. 

Towards  the  end  of  the  "  'seventies  "  very  few  ideas  on  the  con- 
stitution of  silicates  were  promulgated,  the  work  done  at  that  time 
being  chiefly  in  the  direction  of  increasing  the  number  of  observed 
facts  and  improving  the  "observation  material"  from  which  conclu- 
sions might  be  drawn  with  greater  accuracy  and  safety  than  hitherto. 

Such  researches  as  these  made  it  possible  for  Vernadsky34  to 
publish  his  interesting  treatise  on  "The  Sillimanite  Group  and  the 
role  of  Aluminium  in  Silicates . "  A  considerable  time  before  Vernadsky, 
several  authorities  had  agreed  that  aluminium  in  silicates  has  the 
characteristics  of  an  acid  ;  some  presuming  the  existence  of  complex 

*  Special  attention  is  directed  to  Reference  No.  29  in  the  Bibliography  at  the  end 
of  this  volume. 


6  TSCHERMAK'S   AND  VERNADSKY'S  THEORIES 

silicoaluminic  acids  whilst  others  believed  that  aluminium  in  the 
aluminosilicates  plays  the  same  role  as  silicon.  Bonsdorf 35,  as  the  re- 
sult of  investigations  on  hornblendes  containing  alumina  in  which 
the  proportions  of  Si02  and  A1203  vary,  reached  the  conclusion  that 
silicon  and  aluminium  each  play  the  same  role.  Scheerer36  confirmed 
this  view  of  Bonsdorff's.  The  view  that  aluminium  in  the  natural 
silicates  has  an  acid  character  was  also  held  by  Berzelius37,  Bodecker38, 
arid  Odling39. 

Wartha40  was  the  first  to  publish  this  hypothesis  in  a  clear  form, 
but  he  afterwards  paid  more  attention  to  structural  formulae  and  ceased 
to  develop  this  theory.  About  the  same  time,  Brauns41  attributed  an 
acid  character  to  aluminium  in  natural  silicates,  but  instead  of  the 
ordinary  formula,  A1203,  he  preferred  A102. 

Vernadsky  endeavoured  to  show  that  aluminium  plays  the  same 
role  as  silicon  in  the  aluminosilicates  and  that  from  the  latter  complex 
acids  (silicoaluminic  acids)  may  be  produced.  Earlier  observations 
and  experiments  on  aluminosilicates  and  the  chemical  changes  occur- 
ring in  Nature  completely  confirmed  this  view.  At  first,  Vernadsky 
sought  to  base  a  chemical  classification  of  the  aluminosilicates  on  his 
theory,  but  this  could  be  applied  to  only  a  small  number  of  com- 
pounds. Most  of  the  aluminosilicates,  such  as  felspar,  mica,  etc., 
could  not  be  brought  within  any  scheme  he  could  devise,  and  though 
he  repeatedly  declared  that  the  so-called  "  mixture  theories  "  have 
little  real  value  from  a  chemical  point  of  view,  he  believed  that  it  was 
unwise  to  abandon  them. 

Vernadsky 's42  structural  formulae  have  consequently  done  little 
towards  solving  the  problem  of  the  constitution  of  the  silicates. 

The  present  theories  as  to  the  constitution  of  aluminosilicates 
appear,  with  the  exception  of  that  of  Vernadsky,  to  be  combinations 
of  older  theories.  The  existence  of  various  ortho-,  meta-,  and  other 
silicic  and  poly-silicic  acids,  and  of  simple  and  double  salts  of  these,  is 
generally  accepted,  and  to  some  extent  structural  formulae  have  been 
allocated.  The  theories  of  Rammelsberg43,  Groth44,  Clarke45,  Tscher- 
mak46,  and  others  are  of  this  kind.  Those  of  Sawtschenkow47  and, 
more  recently,  of  Goldschmidt48,  differ  somewhat,  as  they  are  based 
on  the  idea  that  the  above-mentioned  silicates  cannot  be  explained 
by  the  foregoing  theories.  The  researches  of  Bombicci49  and  Brauns60, 
which  are  based  on  purely  hypothetical  considerations,  are  quite 
different  from  those  previously  mentioned. 

The  recognition  of  the  acid  nature  of  clays  is  rapidly  gaining 
general  acceptance.  Kaolin  behaves  in  many  ways  precisely  like  an 
acid,  displacing  carbon  dioxide  in  carbonates,  chlorine  in  chlorides, 
etc.,  and  Mellor  and  Holdcroft708  consider  it  to  be  aluminosilicic  acid 
(kaolinic  acid).  These  writers,  like  Vernadsky,  classify  the  alumino- 
silicates according  to  the  ratio  of  A12O3  to  Si02  and  distinguish  them 
as  alumino-raoTio-,  alumino-<fo'-,  alumino-£n'-,  alumino-tfetfra-,  alumino- 
penta-  and  alumino-^eo:a-silicates.  For  instance,  they  regard  nepheline, 


MODERN   THEORIES   OF  ALUMINOSILICATES  7 

Na20  •  A12O3  •  2  Si02  as  a  salt  of  an  alumino-di-silicic  acid  ;  ortho- 
clase,  K20  •  A12O3  •  6  SiO2  as  a  salt  of  an  alumino-hexa-silicic  acid, 
etc.  They  also  suggest  constitutional  formulae  for  these  substances, 
but  without  contributing  materially  to  any  understanding  of  the 
constitution  of  the  aluminosilicates,  as  explained  later. 

W.  Pukall706'  71°  also  refers  to  the  acid  nature  of  kaolin  which, 
when  digested  on  a  water-bath  for  several  days  with  a  solution  of 
caustic  soda,  fixes  a  large  quantity  of  the  soda.  He  has  also  observed 
that  kaolin  at  a  temperature  of  about  950°C.  causes  the  evolution  of 
chlorine  from  common  salt  and  liberates  a  compound  corresponding 
to  Na2O  •  A1203  •  2  SiO2.  Among  other  writers  who  have  recently 
referred  to  the  acid  nature  of  alumina  in  the  aluminosilicates  may  be 
mentioned  J.  Morozewicz711,  who  also  regards  kaolin  as  a  complex 
aluminosilicic  acid. 

An  observation  by  Dalkuhara712  is  highly  confirmatory  of  the  acid 
nature  of  alumina  in  the  aluminosilicates.  It  is  well  known  that  silica 
which  has  been  precipitated  from  solution  and  afterwards  well  washed 
is  neutral  to  litmus.  Dalkuhara  has  examined  various  hydro-silicates, 
particularly  clays,  which  are  acid  to  litmus  and  observed  that,  not- 
withstanding repeated  thorough  washing,  these  silicates  completely 
retained  their  acidity,  no  acid  passing  into  the  wash-water.  If,  how- 
ever, a  neutral  salt  such  as  potassium  chloride,  ammonium  sulphate 
or  ammonium  chloride  is  added  to  the  clay  a  soluble  acid  is  immedi- 
ately produced,  the  potash  or  ammonia  being  absorbed  and  hydrochloric 
or  sulphuric  acid  liberated.  This  is  important  in  connection  with 
another  fact  established  by  Dalkuhara,  viz.  that  finely  divided  felspar 
—which  he  regards  as  a  neutralised  kaolin — on  prolonged  treatment 
with  an  aqueous  solution  of  carbon  dioxide  produces  an  acid-reacting 
silicate  which  behaves  in  a  manner  similar  to  the  clays  just  mentioned. 


Section  II 

Critical  Survey  of  the  Existing  Theories  of  Aluminosilicates 

HpHE  following  hypotheses  or  theories  have  been  formulated  to 
JL    explain  the  constitution  of  the  aluminosilicates  : 

1.  The  aluminosilicates  are  salts  of  silicon  hydrate  in  which  the 
hydrogen  is  partly  replaced  by  aluminium  and  partly  by  other  metals. 

2.  The  aluminosilicates  are  double  salts — silicic  salts  of  aluminium 
and  other  metals — and  also  isomorphous  mixtures  of  these  double 
salts. 

3.  The  aluminosilicates  are  molecular  compounds  composed  of 
various   chemical   compounds   which   have   nothing   in  common  as 


8  CRITICAL  SURVEY  OF  EXISTING  THEORIES 

regards  their  chemical  nature.     The  mode  of  combination  between 
the  various  components  is  very  labile. 

4.  The  aluminosilicates  are  isomorphous  mixtures  of  salts  of  silicic 
and  aluminic  acids. 

5.  The  aluminosilicates  are  double  salts  of  silicic  and  aluminic  acids, 
or  amorphous  mixtures  of  these  double  salts. 

6.  The  aluminosilicates  are,  in  part,  silicoaluminic  acids  and,  in 
part,  the  salts  of  these  acids. 

Before  we  criticise  these  theories  in  the  light  of  the  facts,  it  appears 
desirable  to  make  the  following  statement :  The  aluminosilicates 
constitute  a  single,  well-defined  class  of  compounds,  the  members  of 
which  agree  in  the  numerous  observable  chemical  changes  which  they 
undergo  in  Nature  (the  so-called  pseudomorphic  processes)  and  in 
those  of  their  characteristics  which  are  best  studied  in  the  laboratory, 
such  as  their  synthesis  and  their  behaviour  towards  reagents  and  at 
high  temperatures.  In  these  ways  the  aluminosilicates  differ  con- 
siderably from  silicates  which  are  free  from  aluminium  and  other 
sesquioxides.  No  reaction  is  known  which  makes  it  necessary  to  place 
any  of  these  compounds  in  a  special  class  or  to  give  them  a  special 
place  in  a  separate  class.  They  pass  into  each  other  or  form  the  same 
compounds  ;  they  all  change  slowly  under  the  influence  of  geological 
processes  into  one  and  the  same  compounds  of  the  kaolin  group.  In 
considering  these  hypotheses  we  must  take  special  notice  of  this 
phenomenon  ;  and  in  explaining  the  chemical  nature  of  the  com- 
pounds under  consideration,  only  those  hypotheses  or  theories  should 
be  employed  which  make  it  possible  to  indicate  the  composition  of 
these  compounds  in  a  uniform  manner  and  to  exclude  those  silicates 
which  show  important  differences  of  character.  That  hypothesis  or 
theory  which  agrees  most  closely  with  the  facts  and  is  free  from 
obvious  disadvantages  must  be  regarded  as  the  one  which  approaches 
nearest  to  the  truth. 

(a)  Critical  Examination  of  the  First  Hypothesis 

According  to  the  first  hypothesis  the  aluminosilicates  are  silico- 
hydrates  in  which  one  part  of  the  hydrogen  is  replaced  by  aluminium 
and  another  part  by  other  metals. 

This  theory  contradicts  the  following  facts  : 

1 .  The  relation  between  aluminium  and  the  other  metals  contained 
in  these  compounds  remains  constant  no  matter  how  soon  the  reaction 
of  the  double  decomposition  is  interrupted. 

2.  No  reaction  is  known  whereby  it  is  possible  to  produce  a  hydrate 
of  silicic  acid  from  the  aluminosilicates  and  from  this  hydrate  to 
reproduce  the  original  substance,  i.e.  the  aluminosilicate.    The  separa- 
tion of  silica  by  means  of  strong  acids  is  always  accompanied  by  a 
complete  destruction  of  the  whole  compound.     The  replacement  of 
the  metal  by  hydrogen  usually  occurs  in  such  a  manner  that  only 
those  metals  can  be  substituted  which  are  capable  of  forming  oxides  of 


ARE   ALUMINOSILICATES   SALTS   OF   SILICIC   ACID?      9 

the  R"O  and  R'20  type,  the  aluminium  remaining  unaffected  ;  from 
these  intermediate  products — which  appear  to  be  acid  salts  of  alumin- 
ium— it  is  easy  to  regain  the  original  compounds.  The  replacement 
of  aluminium  by  hydrogen  without  affecting  the  other  metals  has 
not  yet  been  accomplished. 

3.  No  instance  is  known  in  which  all  the  hydrogen  of  the  hypo- 
thetical silicic  hydrate  can  be  replaced  by  a  single  metal,  though  one 
metal  may  be  substituted  for  one  portion  of  it  and  another  metal  for 
the  remainder.    Thus,  the  transformation  of  Si  Al  NaO  4  into  Si  Na40  4, 
or  the  reverse,  by  means  of  a  double  decomposition  is  impossible. 

4.  If  it  is  desired  to  use  this  hypothesis  in  the  study  of  the  alumino- 
silicates  and  to  apply  it  to  all  of  these  compounds,  it  is  necessary  to 
conceive   the   existence   of   highly   complex   and   improbable   silicic 
hydrates  or  of  basic  salts.     Even  then,  this  hypothesis  affords  no 
assistance  for  many  compounds,  such  as  the  sapphires. 

5.  If  this  hypothesis  is  accepted,  the  simple  reactions  which  occur 
with  these  compounds  cannot  be  explained.    For  example,  the  trans- 
formation of  one  aluminosilicate  into  another  has  frequently  been 
observed,  the  ratio  of  alumina  to  the  R"O  and  R'2O  oxides  remaining 
unchanged  and  only  the  ratio  of  silica  to  these  oxides  varying  ;    e.g. 
reactions  in  which  an  increase  or  diminution  of  Si02  occurs.     Such 
reactions   are  by  no   means   uncommon:    orthoclase,   K20-A1203- 
6Si02  easily  passes  into  leucite,  K2O  •  A1203  •  4Si02;  and  later  into 
muscovite,  K20  -H2O  •  2  A1203  •  4Si02.     Analogous  changes  are  the 
transformation  of  albite  into  kaolin  and  mica  ;    the  formation  of 
analcime  Na2O  •  A1203  •  4Si02-2H20  from  nepheline  ;  the  conver- 
sion of  analcime  into  muscovite  and  the  artificial  production  of  it 
from  orthoclase,  albite  and  kaolin  ;   the  transformation  of  andalusite, 
A1203  •  Si02  into  muscovite51  ;  the  conversion  of  kaolin  into  analcime 
by  means  of  sodium  silicate52,  the  formation  of  kaolin  from  nephe- 
line53, the  conversion  of  elaolite,  Na2O  •  A1203  •  2Si02  into  natrolite54, 
Na20  •  A1203  •  3Si02  •  2H20,  into  analcime55  and  into  hydronephe- 
lite56,  Na20  -H20  •  2A1203  •  6Si02  -  2H20  ;    and  in  the  passage  of 
muscovite  into  leucite  by  the  action  of  Si02  in  the  presence  of  alkali 
carbonates57.    These  reactions,  selected  from  a  much  larger  number, 
are  quite  inexplicable  by  the  first  hypothesis. 

It  is,  therefore,  scarcely  conceivable  that  those  constitutional 
formulae  of  the  aluminosilicates  which  are  based  on  the  first  hypothesis 
are  in  accordance  with  the  facts. 

Recently,  several  mineralogists,  including  Brogger58,  Clarke59, 
Groth60,  endeavoured  to  use  the  first  hypothesis  by  presuming  the 
existence  of  several  complex  aluminium  radicles  such  as  A1C1,  A1F2, 
A1O,  etc.,  which  replace  metals  and  can  form  RO  oxides.  Unfor- 
tunately, no  chemical  reactions  are  known  in  support  of  this  hypo- 
thesis, which  is  entirely  based  on  the  arrangement  of  the  silicates 
according  to  their  crystalline  form. 

Moreover,  this  modified  hypothesis  gives  little  or  no  explanation 


10  CRITICAL  SURVEY  OF  EXISTING  THEORIES 

of  the  constitution  of  the  chemical  compounds  just  mentioned,  and, 
all  things  considered,  it  must  be  admitted  that  the  first  hypothesis 
does  not  explain  the  reactions  to  which  reference  has  been  made. 


(I)  Critical  Examination  of  the  Second  Hypothesis 

The  second  hypothesis  (that  the  aluminosilicates  are  double  salts 
of  aluminium  and  other  metals  and  that  they  also  comprise  isomorphous 
mixtures  of  these  double  salts)  is  one  of  the  oldest.  It  was  originated 
by  Berzelius  and  Smithson. 

The  following  objections  to  this  hypothesis  require  consideration  : 

1.  Any  reaction  in  which  the  proportion  of  silica  in  the  compound 
varies  whilst  the  proportion  of  aluminium  to  base  remains  constant  is 
inexplicable. 

2.  This  hypothesis  requires  the  existence  of  very  stable  double 
salts  of  different  silicic  acids,  or  of  double  salts  composed  of  both 
normal  and  basic  salts.    It  cannot  be  said  that  the  production  of  double 
salts  from  salts  of  different  basicity  or  acidity  is  impossible,  as  our 
knowledge  of  the  double  salts  is  far  from  complete. 

The  existence  of  such  salts  is,  however,  highly  improbable  and  if 
this  hypothesis  were  correct  it  would  necessitate  the  placing  of  such 
salts  in  a  class  by  themselves,  as,  amongst  all  the  substances  which 
have  been  investigated,  no  such  double  salts  have  been  observed. 

3.  How  is  it  possible  to  term  compounds  having  the  general 
formula : 

R20  •  A1203  •  Si02 

double  salts  ?     These  compounds  occur  in  Nature  and  may  also  be 
prepared  artificially.    As  naturally  occurring  minerals :  CaO  •  2  A1203 

•  2  Si02  •  H20  (Margarite61)  and  MgO  •  A1203  •  SiO2  (Prismatine62)  may 
serve  as  examples  of  this  group.    Artificially  prepared  K20  •  A12O3 

•  Si02  and  Na2O  •  A1203  •  Si02  form  typical  synthetic  products.63 

All  these  compounds  are  closely  related  to  compounds  in  other 
groups  ;  thus  K20  •  A1203  •  Si02  and  Na2O  •  A12O3  •  Si02  readily 
change  into  K2O  •  A1203  •  2  Si02  and  Na2O  •  A12O3  •  2  Si02  respec- 
tively, and  inversely  they  may  both  be  obtained  from  kaolin.64  Mar- 
garite is  closely  related  to  the  micas  and  is  not  infrequently  formed 
from  them.65  Prismatine  changes  into  a  hydrous  silicate  (Krypolite) 
which,  according  to  this  hypothesis,  must  be  regarded  as  a  double 
salt  and  in  the  form  of  phlogopite  may  be  obtained  artificially.66 

There  is  clearly  a  genetic  relationship  between  the  various  alumino- 
silicates, but  to  regard  them  as  double  salts  it  would  be  necessary  to 
provide  a  special  space  in  the  scheme  of  classification,  as  there  are 
many  compounds  of  this  group  (which  can  never  be  termed  double 
salts)  for  which  no  provision  is  made. 

4.  The  fact  that  compounds  which,  from  the  point  of  view  of  those 
who  accept  this  hypothesis,  are  very  complex  in  structure  are  found 


ARE   ALUMINOSILICATES   DOUBLE   SALTS?  11 

on  experiment  to  be  very  stable,  is  puzzling.  Thus  the  group  R2O 
•  A12O3  •  2  SiO2,  into  which  practically  all  other  aluminosilicates  may 
be  readily  converted,  is  characterised  by  its  exceptional  stability. 
Those  who  accept  this  hypothesis  regard  the  compounds  of  this  group 
as  double  salts,  having  the  general  formula  : 

3  +  Al2Si05     or     R'2Si03  -f  R'6SiO5, 


i.e.  as  normal  salts  of  meta-silicic  acid  with  a  basic  salt  of  some  other 
silicic  acid.  It  is  scarcely  conceivable  a  priori  that  the  representatives 
of  the  most  stable  substances  of  the  whole  class  of  aluminosilicates 
are  to  be  found  in  compounds  of  this  composition. 

5.  To  the  view  that  the  aluminosilicates  are  double  salts  there  is 
also  the  following  objection  :  The  term  "double  salt  "  is  by  no  means 
clearly  defined  and  gives  but  little  definite  information  as  to  the  nature 
of  the  compounds  to  which  it  is  applied.  This  term  should,  therefore, 
be  used  more  cautiously  than  is  sometimes  the  case  and  should  only 
be  applied  to  those  substances  of  which  the  mode  of  formation  from 
their  constituent  salts  is  clearly  ascertainable.  For  example,  it  is 
quite  correct  to  term  the  compound  K2Mg(SO4)2  •  6  aq.  a  double  salt, 
because  it  can  be  produced  directly  from  the  two  constituent  salts, 
K2S04  and  MgSO4.  But  can  such  syntheses  be  observed  in  the  case 
of  aluminosilicates  ?  Can  any  analogous  reaction  be  found  among  the 
innumerable  compounds  of  silica  ?  The  syntheses  which  have  actually 
been  effected  suggest  the  exact  opposite  of  the  second  hypothesis  and 
are  most  puzzling  when  an  attempt  is  made  to  apply  it  to  them.  No 
syntheses  in  support  of  this  hypothesis  have  yet  been  made. 

It  is  impossible  by  this  hypothesis  to  explain  the  formation  of 
compounds  such  as  analcime,  Na20  •  A1203  •  4  Si02  •  2  H20  (which  is 
produced67  by  the  action  of  Na2Si03  on  NaA102),  or  of  other  alumino- 
silicates which  are  obtained  from  silicates  and  aluminates.68  In 
these  compounds  aluminates  are  found,  but  no  aluminium  silicates,  a 
circumstance  which  is  quite  contrary  to  the  conception  of  alumino- 
silicates as  double  salts. 


(c)  Critical  Examination  of  the  Third  Hypothesis 

According  to  the  third  hypothesis,  the  aluminosilicates  may  be 
regarded  as  molecular  compounds,  i.e.  compounds  in  which  the  unit 
of  combination  is  a  molecule  and  not  an  atom. 

This  conception  of  the  constitution  of  natural  silicates  has  chiefly 
been  favoured  by  Bombicci69  and  V.  Goldschmidt,  others  only  having 
applied  it  to  a  few  specific  cases,  as  Mallard70,  who  used  it  to  explain 
the  constitution  of  chondrodite. 

Some  silicates  are  undoubtedly  molecular  compounds,  particularly 
those  silicates  which  contain  water  of  crystallisation.  Some  researches 
of  Lemberg71  and  Doelter72  indicate  that  cancrinite  is  a  molecular 
compound  and  other  investigations  by  Lemberg  and  Thugutt  lead  to 


12  CRITICAL   REVIEW   OF   EXISTING   THEORIES 

the  conclusion  that  the  sodalites  are  also  molecular  compounds. 
Other  natural  silicates  appear  to  confirm  this  view,  so  that  at  first 
sight  it  seems  as  if  this  hypothesis  would  enable  the  facts  to  be  satis- 
factorily explained ;  in  reality,  the  facts  are  in  direct  contradiction  to 
the  theory.  A  closer  investigation  shows  that  any  agreement  between 
fact  and  theory  which  may  occur  is  a  coincidence  due  to  the  indefinite- 
ness  of  the  latter  ;  this  indefiniteness  makes  a  large  number  of  sup- 
positions possible.  Many  facts,  whilst  not  exactly  in  opposition  to  it, 
cannot  be  used  in  support  of  this  theory  because  they  cannot  be  pre- 
dicted from  it.  For  this  reason,  this  hypothesis  has  not  the  value  of  a 
true  scientific  theory  or  "  law  of  Nature,"  one  essential  feature  of 
which  is  the  facilities  it  offers  for  the  prediction  of  properties  of  sub- 
stances from  a  knowledge  of  their  constitution. 

The  very  indefiniteness  of  the  term  "molecular  compound" 
allows  the  formulation  of  innumerable  theories  and  makes  it  ex- 
tremely difficult  to  decide  which  of  these  are  of  value  and  which  are 
merely  ingenious  speculations.  To  make  this  clearer  it  may  be  assumed 
for  the  moment,  that  the  compound 

K20  •  A1203  •  6  Si02 

is  composed  of  two  or  more  molecules.  In  selecting  these  there  is  an 
enormous  number  of  possible  molecular  compounds  to  choose  from, 
all  of  which  correspond  to  the  formula  of  orthoclase  given  above. 
For  instance,  there  are 

1.  K2Al2Si208  +  4  Si02, 

2.  K2Si03  +  Al2Si05  -f  4  Si02, 

3.  K2Si03  +  Al2Si308  +  2  Si02,  etc. 

ad  infinitum. 

It  is  clear  that  from  the  formula  for  orthoclase,  taken  as  an  example, 
as  many  different  molecular  compounds  can  be  written  out  as  there 
are  mathematical  combinations  of  symbols  of  the  elements  avail- 
able. If  one  of  these  hypothetical  formulae  is  found  not  to  repre- 
sent the  characteristics  of  the  substance  under  consideration,  a  second, 
third,  fourth,  and  so  on,  is  substituted.  The  matter  is  still  further 
complicated  by  the  indefiniteness  of  the  term  "  molecular  compound  " 
as  used  by  different  writers  ;  an  indefiniteness  which  enables  those 
who  use  it  to  indulge  in  all  manner  of  speculations. 

Broadly  speaking,  there  is  no  definite  means  of  deciding  whether 
a  given  substance  should  be  regarded  as  a  molecular  or  as  an  atomic 
compound.  Usually,  those  substances  are  regarded  as  molecular 
compounds  which  cannot  be  otherwise  understood,73  the  subjective 
conception  of  each  individual  scientist  being  the  factor  which  deter- 
mines whether  he  will  regard  a  given  chemical  compound  as  molecular 
or  atomic.  Some  chemists  regard  the  so-called  "  double  salts  "  as 
molecular  compounds,  whilst  others  regard  some  of  these  salts  as 
atomic  and  the  remainder  as  molecular  compounds.  This  shows  that 
great  caution  is  necessary  in  using  these  terms  for  the  solution  of 


ARE   ALUMINOSILICATES   MOLECULAR   COMPOUNDS?     13 

theoretical  questions.  In  Science,  it  is  only  in  rare  cases  that  a  theory 
can  be  used  which,  on  account  of  its  indefiniteness  and  lack  of  clearness, 
does  not  possess  all  the  requirements  of  a  scientific  hypothesis. 

If  aluminosilicates  are  molecular  compounds  they  must  show 
definite  properties  characteristic  of  their  constitution.  This  is  not  the 
case.  Molecular  compounds  are  formed  of  chemical  compounds  of 
definite  composition  (Molecules)  and  must  necessarily  be  less  stable 
than  atomic  compounds,  as  the  force  which  binds  molecules  together 
must,  naturally,  be  weaker  than  that  which  unites  atoms  to  form 
molecules.  Under  many  conditions,  such  as  solution  in  water,  or 
when  under  the  action  of  heat  or  chemicals,  molecular  compounds 
split  up  into  their  component  molecules.  Many  aluminosilicates  show 
a  high  degree  of  stability  ;  some  can  be  dissolved  and  afterwards  con- 
verted into  the  solid  state  without  undergoing  the  least  decomposition 
(e.g.  CaO  •  A1203  •  2  Si02,  Na20  •  A1203  •  2  Si02,  etc.).  The  decom- 
position-products formed  when  aluminosilicates  are  heated  are  usually 
complex  and  can,  more  reasonably,  be  termed  molecular  compounds. 
Thus,  the  majority  of  the  calcareous  aluminosilicates  form  CaO  •  A1203 

•  2  Si02,  and  analogous  compounds.74     The  reactions  of   these  ap- 
parent components  take  no  part  in  the  chemical  reactions  of  the 
aluminosilicates. 

The  indefiniteness  of  the  theory  here  criticised  and  the  absence  of 
facts  in  support  of  it  show  definitely  that  it  does  not  suffice  to  give 
a  clear  idea  of  the  constitution  of  the  aluminosilicates.  This  very 
indefiniteness  of  the  hypothesis  is  also  a  reason  why  it  is  impossible  to 
find  many  facts  which  can  be  used  in  direct  disproof  of  it. 

(d)  Critical  Examination  of  the  Fourth  and  Fifth  Hypotheses 

According  to  the  fourth  hypothesis,  aluminium  and  silicon  both 
play  the  part  of  acid-forming  elements  ;  and  the  aluminosilicates  are 
regarded  as  isomorphous  mixtures  of  aluminates  and  silicates.  As  no 
facts  are  available  which  show  that,  in  natural  silicates,  aluminium 
plays,  to  some  extent,  the  part  of  acid-  and,  to  some  extent,  that 
of  a  base-forming  element,  it  may  be  assumed  that  in  the  silicates  the 
aluminium  is  present  as  aluminic  acid  and  has  not  replaced  part  of 
the  hydrogen  of  the  silicic  hydrate. 

This  view  renders  the  constitution  of  a  large  number  of  alumino- 
silicates quite  inexplicable,  particularly  those  with  less  base  than  is 
required  by  the  number  of  hydroxyl  groups  of  the  corresponding 
silicic  and  aluminic  hydrates,  e.g.  K20  •  A1203  .  4Si02,  K2O  •  A1203 

•  6Si02.    This  hypothesis  also    fails  to  explain  the  proved   forma- 
tion of  silicates  containing  alumina  by  the  decomposition  of  alumino- 
silicates and  the  invariable  occurrence  of  alumina  and  silica  in  the 
products  of  the  reaction.    Indeed,  this  hypothesis  indicates  precisely 
that  the  contrary  should  be  expected,  viz.  ready  decomposition  into 
aluminates  and  silicates,  as  the  valencies  of  the  constituents  of  isomor- 


14  CRITICAL  REVIEW  OF  EXISTING  THEORIES 

phous  mixtures  (of  aluminates  and  silicates)  are  naturally  weaker 
than  those  of  the  atoms  which  form  the  components  of  the  mixtures. 

The  confirmation  of  this  hypothesis  by  the  synthesis  of  alumino- 
silicates  from  aluminates  and  silicates  is  more  apparent  than  real,  as 
the  ratio  of  base  :  aluminium  :  silica  in  the  products  of  the  reaction 
is  quite  different  from  that  which  would  be  found  if  aluminates  and 
silicates  could  form  isomorphous  mixtures.  Thus,  analcime,  NaAlSi206 
•  aq.  and  similar  substances  are  producible  from  Na2Si03  and  NaA102. 
Moreover,  it  has  never  been  proved  that  the  salts  of  aluminosilicic 
acids  are  isomorphous,  and  to  attribute  this  character  to  them  is  pure 
hypothesis.  A  similarity  is  often  observed  in  the  forms  of  crystals, 
e.g.  chrysoberyl  and  olivine,  but  except  for  this  single  resemblance 
no  evidence  has  been  given  of  isomorphism.  No  actual  observations 
of  isomorphous  mixtures  produced  directly  from  aluminates  and 
silicates  have  ever  been  published. 

But  little  importance  can,  therefore,  be  attached  to  the  fourth 
hypothesis,  as  it  is  only  applicable  in  special  cases  (such  as  those 
investigated  by  Rammelsberg75,  Knop76,  and  others)  and  has  never 
been  of  general  application  to  the  study  of  the  constitution  of  the 
aluminosilicates . 

The  foregoing  hypothesis  may  be  somewhat  modified  so  as  to 
indicate  that  isomorphous  mixtures  of  aluminates  and  silicates  and 
isomorphous  mixtures  of  double  salts  having  aluminates  and  silicates 
as  their  components,  may  be  formed  along  with  the  aluminosilicates. 
This  leads  directly  to  the  fifth  hypothesis.  Yet,  even  in  this  form,  the 
facts  do  not  agree  with  the  theory.  The  invariable  presence  of  alumin- 
ium and  silica  appears  to  be  inexplicable — the  contrary  appears  to 
be  more  probable — the  reaction  products  must,  if  this  hypothesis  is 
correct,  contain  either  silicon  or  aluminium,  but  not  silicon  and 
aluminium  in  one  and  the  same  product. 

According  to  the  fourth  and  fifth  hypotheses,  those  aluminosilicates 
which  consist  exclusively  of  Si02  and  A1203  appear  to  occupy  a  special 
position,  yet  between  them  and  other  aluminosilicates  an  undoubtedly 
genetic  relationship  is  shown  to  exist  by  the  ease  with  which  they 
can  be  transformed  into  one  another.  The  first  contain  no  alkali  and 
cannot,  for  that  reason,  be  regarded  as  isomorphous  mixtures  or 
double  salts  of  aluminates  and  silicates.  If,  however,  these  substances 
are  to  be  regarded  as  aluminium  salts  of  silicic  acid,  the  alumino- 
silicates must,  under  other  circumstances  or  in  other  cases,  be  shown 
to  be  so  constituted  that,  in  them,  the  aluminium  has  replaced  the 
water  of  the  silicic  hydrate  ;  yet  this,  if  true,  destroys  the  fourth  and 
fifth  hypotheses.  The  compounds  last  mentioned  cannot  be  regarded 
as  isomorphous  mixtures  of  A12O3  and  Si02,  as  the  isomorphism  of 
these  compounds  still  remains  to  be  proved  ;  moreover,  the  existence 
of  an  invariably  simple  ratio  of  alumina  to  silica  is  also  opposed  to 
such  an  isomorphism. 

Similarly,  the  constitution  of  those  aluminosilicates  which  contain 


ARE   ALUMINOSILICATES   ISOMORPHOUS   MIXTURES?     15 

water  in  addition  to  A12O3  and  Si02  is  very  puzzling  if  studied  in 
connection  with  these  hypotheses. 

Hence,  the  fourth  and  fifth  hypotheses  cannot  be  used  to  explain 
the  constitution  of  the  aluminosilicates. 

(e)  Critical  Examination  of  the  Sixth  Hypothesis 

According  to  the  sixth  hypothesis,  the  aluminosilicates  are  com- 
plex acids  or  the  salts  of  complex  acids.  They  are,  therefore,  analogous 
to  the  silicotungstates,  arsenomolybdates,  silicomolybdates,  phos- 
phomolybdates,  etc.  All  the  substances  just  mentioned  have  been 
placed  in  a  new  group  by  Wolcott  Gibbs77,  though  some  facts  which 
indicated  the  existence  of  complex  acids  were  known  long  before 
Gibbs'  work  was  published. 

Before  making  any  statement  as  to  the  value  of  this  hypothesis  in 
the  study  of  the  constitution  of  the  aluminosilicates  the  following 
questions  must  be  clearly  answered  : 

I.  To  what  results  do  previous  chemical  and  physico-chemical 
researches  on  the  complex  acids  and  their  salts  lead,  as  regards  their 
chemical  nature  ? 

II.  What  theories  have  been  formulated  with  regard  to  the  chemical 
constitution  of  the  complex  acids  and  what  is  the  value  of  these 
various  theories  ? 

With  regard  to  the  first  question  the  following  statement  may  be 
made  : 

(a)  The  properties  of  the  complex  acids  producible  from  a  series 
of  acids  such  as  tungstic,  molybdic,  vanadic,  phosphoric,  arsenic, 
silicic,  antimonic,  and  other  acids  by  the  combination  of  two  or  more 
of  these  acids  (as  silicic  and  tungstic,  phosphoric  and  molybdic,  etc.) 
in  definite  proportions  do  not  completely  coincide  with  the  sum  of 
the  properties  of  their  components. 

(b)  The  acidity  of  the  complex  acids  is  seldom  equal  to  that  of 
the  separate  acids  from  which  the  complex  one  has  been  formed. 

(c)  Any  given  acid  can  usually  unite   in    variable — but  simple 
—proportions  to  form  several  complex  acids. 

(d)  The  complex  acids  can  exist  either  in  the  free  state  or  as  salts. 

(e)  When  complex  acids  take  part  in  a  double  decomposition,  no 
separation  of  the  component  acids  occurs.    The  latter  are  found  in  the 
new  product  in  the  same  proportion  as  they  were  in  the  original  com- 
plex acid.* 

(/)  The  conversion  of  one  complex  acid  into  another,  composed  of 
the  same  constituent  acids,  is  easily  effected  by  splitting  off  one  of  the 
acids  in  the  form  of  a  salt  or  in  the  free  state.  Thus,  the  conversion  of 
one  phospho-tungstic  acid  into  another  is  accomplished  by  the  removal 
of  tungstic  acid  or  one  of  its  salts. 

*  In  other  words  a  complex  acid  acts  as  a  single  acid  and  not  as  a  mixture  of 
two  or  more  separate  acids. — A.  B.  S. 


16  CRITICAL  REVIEW   OF  EXISTING  THEORIES 

(g)  From  the  corresponding  anhydrides  a  series  of  complex  radicles 
may  be  produced,  the  ratios  of  the  constituents  of  the  anhydrides 
being  always  simple. 

(h)  Great  difficulties  are  experienced  if  such  compounds  as  the 
silicotungstates,  phosphotungstates,  etc.  are  classified  in  accord- 
ance with  Ostwald's78  definition  of  double  salts,  and  if  any  attempt  is 
made  to  divide  true  complex  acids  into  two  groups  according  to  their 
behaviour  in  aqueous  solution.  The  recent  physico-chemical  study 
of  these  compounds — made  with  a  view  to  ascertaining  their  constitu- 
tion79— has  shown  that  whilst  some  dissociate,  when  in  aqueous 
solution,  into  their  components,  others  are  quite  stable.  The  former, 
according  to  Ostwald's  classification,  must  be  regarded  as  "double 
salts  "  and  the  latter  as  "  complexes."  In  some  cases,  as  (1)  when  a 
"  double  salt "  contains  alkali  or  (2)  with  certain  proportions  of  acid 
and  alkali,  the  use  of  the  term  "  double  salt  "  is  permissible.  With 
many  of  these  compounds  this  is  not  the  case,  e.g.  free  acids  and  those 
which  contain  a  much  larger  proportion  of  one  of  the  acids  than  of 
the  other.  For  instance,  how  is  it  possible  to  represent  the  free  acid 

3  H20  •  P206  •  24  W03, 

as  a  double  salt  ?  Yet  the  physico-chemical  researches  of  Sobolew80 
(dialysis,  electrical  conductivity,  etc.)  have  shown  that  in  aqueous 
solution  it  dissociates  into  phosphoric  acid  and  metatungstic  acid  and 
that  its  salts  are  equally  unstable  in  the  presence  of  water. 

The  division  of  the  compounds  under  consideration  into  two 
groups  according  to  their  behaviour  when  in  aqueous  solution  does  not 
appear  to  be  satisfactory.  On  the  contrary,  the  experimental  results 
make  it  appear  far  more  probable  that  all  the  compounds  in  this  group 
are  of  analogous  constitution,  though  they  vary  in  their  stability  when 
in  aqueous  solution.  The  following  facts  appear  to  confirm  this  view  : 

1.  W.  Asch776  has  shown  by  means  of  a  physico-chemical  investiga- 
tion  (dialysis,   electrical  conductivity,   determination   of  molecular 
weight,  etc.)  of  the  silico-molybdate 

2  K/20  •  SiO2  •  12  Mo03  •  aq., 

that  in  these  compounds  the  silicic  and  molybdenic  acids  form  a 
complex  ion.  This  is  confirmed  by  the  production  (by  the  same 
investigator)  of  readily  soluble  barium  and  calcium  salts  of  the  same 
series,  having  the  general  formula 

2  R"0  •  Si02  •  12  MoO3  •  aq.     (R*  =  Ba,  Ca), 
and  acid  salts  with  a  composition  corresponding  to  : 

1.5  R20  •  0.5  H20  •  Si02  •  12  Mo03  •  aq.     (R'  =  K,  Na). 

2.  D.  Asch777  has  prepared  compounds  with  the  general  formula 

2  R20  •  2  S02  •  5  Mo03  •  aq.     (R'  =  K,  Na,  NH4), 


ARE  ALUMINOSILICATES  COMPLEX  ACIDS  OR  SALTS?     17 

by  the  action  of  sulphurous  acid  on  the  alkalies  of  the  paramolybdates. 
These  compounds,  unlike  the  silicomolybdates,  are  very  unstable  in 
water,  so  that  the  conversion  of  the  alkali-salts  just  mentioned  into 
the  corresponding  salts  of  the  alkaline  earths  appears  to  be  impossible 
on  account  of  the  decomposition  of  the  latter  in  water.  Only  by  the 
use  of  concentrated  alkali-paramolybdate  solutions  saturated  with 
SO  2  gas,  together  with  the  salts  of  the  alkaline  earths,  was  it  found 
possible  to  prepare  readily  soluble  salts  of  the  alkaline  earths  corre- 

sponding: to 

2  R"O  •  2  S02  -  5  Mo03  •  aq.     (R"  =  Ba,  Sr,  Ca). 

Consequently,  there  can  be  no  doubt  that  the  sulphurous  molyb- 
dates  —  in  spite  of  their  ready  decomposition  when  in  aqueous  solution 
—  must,  on  account  of  the  manner  in  which  they  form  readily  soluble 
salts  of  the  alkaline  earths,  be  regarded  as  salts  of  a  complex  sulpho- 
molybdic  acid  with  the  formula 

2  H20  •  2  S02  •  5  Mo03  •  ag. 

It  is  here  assumed  that  the  compounds  under  consideration  may 
be  regarded  either  as  free  complex  acids  or  their  salts,  some  of  these 
substances  being  stable  in  aqueous  solution  whilst  the  remainder  are 
more  or  less  unstable. 

An  answer  to  the  questions  (p.  15)  concerning  the  previous  theories 
of  the  constitution  of  complex  acids  and  their  salts  may  now  be  given. 

It  should  be  observed  that  most  investigators  of  these  complex 
acids  and  their  salts  have  been  content  to  accept  the  chemical  com- 
position without  making  the  smallest  effort  to  theorise  on  the  chemical 
nature  of  these  compounds.  Although  the  number  of  these  substances 
is  somewhat  large,  the  theories  of  their  constitution  are  comparatively 
few,  and  even  these  are  not  free  from  objections.  Amongst  them, 
structural  formulae  are  of  importance  and  have  been  employed  by 
several  investigators  to  indicate  the  chemical  nature  of  several  complex 
compounds.  Thus,  Fremery778  endeavoured  to  represent  by  structural 
formulae  the  arsenotungstates  he  prepared.  Later,  Friedheim84, 
Blomstrand85,  Kehrmann86,  Sprenger87,  Michaelis88  and  others  en- 
deavoured to  follow  Fremery's  example  and  to  apply  analogous 
structural  formulae  to  quite  different  substances.  Notwithstanding 
the  fact  that  the  structural  formulae  of  Blomstrand  and  Friedheim  are 
analogous,  the  theories  of  these  two  investigators  are  quite  distinct. 

Blomstrand89  compares  the  ability  of  the  acid  anhydrides  to  com- 
bine in  various  proportions  to  form  complex  anhydrides,  with  that  of 
those  salts  of  cobalt,  rhodium,  platinum  and  gold  which  can  combine 
with  ammonia  in  such  a  manner  as  to  form  "  chains  "  containing 
1  NH3  to  3  NH3. 

He  suggests  the  following  equations  to  show  the  combination  of 
ammonia  with  the  metallic  salts  mentioned  : 


+  NH3  =  MNH.C1, 
MCI  +  2  NH3  =  MNH3  •  NH3C1,  etc. 


18          CRITICAL  REVIEW   OF  EXISTING  THEORIES 

He  regards  the  formation  of   the   following   complex   acids  as 
analogous  : 

OX  =  (OH),  +     OM02  = 


OX  =  (OH),  +  2  OM02  =  OX<°M02  •  OM02OH, 

etc. 


He  considers  that  what  occurs  is  the  automatic  opening  of  the 
atomic  complex  and  the  introduction  of  the  new  group,  member  for 
member,  whenever  this  is  possible  without  changing  the  general 
character  of  the  whole  substance. 

Friedheim90  regards  the  course  of  the  reaction  in  the  formation  of 
complex  acids  in  an  entirely  different  manner.  For  instance,  he 
represents  the  first  stage  of  the  reaction  of  molybdic  acid  on 
NaH2As04  as  a  combination  of  the  molybdic  acid  with  the  base^of 
the  arsenic  salt  as  follows  : 

8  -f  Mo03  +  aq.  =  2  OAs(OH)3  +  Na2Mo04 

+  2  Mo03  +  aq.  =  2  OAs(OH)3  +  Na2Mo207,  etc. 

In  addition  to  these  molybdates,  acid  molybdates  will  also  pass  into 
solution,  thus : 

HO  •  Mo02  •  ONa, 

HO  •  MoO2  •  OMoO,  •  ONa, 

HO  •  MoOa  •  OMoO,  •  OMo02  •  ONa,  etc. 

These  are  unstable  and  unite  with  the  free  arsenic  acid  with  loss 
of  water  : 

X0|H      H0|  •  Mo02  •  ONa 
OAsr-OH 


IH      HO 


/2P 

OAs^-Q|H      HO 

XrkTT  etc. 


Mo02  •  OMo02  •  ONa 
Mo02  •  OMoO,  •  ONa, 

Provided  that  the  hydroxyl  groups  of  the  acid  OX=(OH)3  do  not 
split  off  automatically  with  formation  of  water,  the  hydrogen  of  these 
hydroxyl  groups  may  be  replaced  by  R,  the  following  examples  being 
theoretically  possible  : 

/OMo02  •  OMo02  •  ONa 
OAsf-ONa 
\ONa 

/OMo02  •  OMoO2  •  ONa 
OAs;-OMoOa  •  OMo02  •  ONa  . 

\ONa  etc. 

The  foregoing  structural  formulae  are  open  to  the  following  objec- 
tions : 

1 .  It  appears  as  if  the  acidity  of  the  complex  molybdates  or  tung- 
states  is  quite  independent  of  the  amount  of  metallic  acid  (molybdic 


ARE  ALUMINOSILICATES  COMPLEX  ACIDS  OR  SALTS?     19 

or  titanic  acid)  in  the  complex  and  is  only  influenced  by  the  atomicity 
of  those  substances  with  which  the  metallic  acids  combine  to  form  a 
complex.  Thus,  Pufahl91  has  decomposed  a  compound  of  the  series 

3  R20  •  As205  •  18  Mo03  •  aq., 

with  silver  or  thallium  salts,  and  has  produced 

6  Ag20  •  As2O5  •  18  Mo03  •  aq.,  and 
6  T12O  •  As205  •  18  Mo03  •  aq. 

These  compounds  contain  twice  as  much  base  as  is  theoretically 
possible. 

As  Friedheim  writes  the  structural  formulae  of  the  compound 

3  R20  •  As20s  •  18  Mo03 
as 

As  =  (OMo02  •  OMo02  •  OMo02  •  OR)3 


\/ 

As  ==  (OMo02  •  OMo02  •  OMoO2  •  OR)3, 

which  is  analogous  to  the  structural  formula  previously  mentioned, 
he  must  place  the  compounds  with  6  R20  in  a  separate  class  on  account 
of  their  proportion  of  base.  He  denotes  the  constitution  of  such  sub- 
stances as  molecular,  i.e.  he  attempts  an  explanation  which,  on  account 
of  its  confused  nature,  is  no  explanation  at  all. 

The  number  of  such  compounds  with  a  high  proportion  of  base  is 
somewhat  large  and  it  is  sufficient  to  mention  the  following : 

(a)  6  R20  •  As205  •  18  MoO3  92 
(6)  4  R20  •  B203  •  12  Wo03  93 

(c)  4  R2O  •  Si02  •  12  Wo03  " 

(d)  7  R2O  •  V2O5  •  12  WoO3  95,  etc. 

To  agree  with  Friedheim's  and  Blomstrand's  theory,  the  series  (a), 
(b)  and  (d)  can  at  most  contain  3  R20  and  (c)  only  2  R20  !  There  is  no 
real  reason  for  placing  all  these  compounds  in  a  separate  class,  for 
neither  in  their  properties  nor  in  their  mode  of  formation  do  they 
differ  from  those  from  which  the  above  structural  formulae  were 
derived. 

2.  Another  weakness  of  the  hypotheses  of  Blomstrand  and  Fried- 
heim is  that  they  do  not  permit  of  deductions  being  made  in  connection 
with  the  compounds  of  the  complex  acids  containing  the  elements  just 
mentioned,  and  that  the  composition  of  only  a  relatively  small  number 
of  the  compounds  in  this  class  can  be  represented  structurally  in  the 
way  they  suggest. 

Moreover,  there  cannot  be  sufficient  evidence  for  the  proposed 
structural  representation,  as,  for  the  majority  of  these  compounds, 
these  two  investigators  have  been  contented  with  the  use  of  empirical 
formulae  and  have  not  made  the  smallest  attempt  to  determine  thek 


20  CRITICAL   REVIEW  OF   EXISTING   THEORIES 

constitution.  This  is  probably  due  to  the  complexity  of  many  of 
these  compounds.  Thus,  no  hypotheses  have  been  formulated  for 
compounds  containing  15,  16,  17,  20  and  22  R03  (R=Mo,  W)  to  one 
molecule  of  X206  (X=As,  P,  Vd).  Some  of  these  compounds  have 
been  prepared  from  substances  to  which  the  structural  formulae  apply 
and  their  molecular  arrangement  is  then  of  interest.  Thus,  Sprenger96, 
working  with  a  barium  salt  of  the  series  P205  •  24  W03  and  Ba(OH)2 
according  to  the  equation 

3  BaO  •  P205  •  24  W03  +  6  Ba(OH)2 
=  7  BaO  •  P205  •  22  W03  +  2  BaW04  +  6  H20, 

obtained  a  member  of  the  series  P205  •  22W03 — a  reaction  which 
admits  of  no  explanation  in  terms  of  the  above  theory  ! 

Kehrmann  and  Freinkel  have  prepared  other  compounds  of  this 
series,  viz. : 

1.  3  BaO  •  4  Ag20  •  P205  •  22  W03  aq,  and 

2.  7  K2O  •  P205  •  22  W03  aq. 

Kehrmann97  has  also  prepared  from  the  compound  2,  by  means  of 
hydrochloric  acid  and  potassium  chloride,  a  crystalline  substance  with 
the  formula 

5  K20  •  P2O5  •  17  W03. 

All  these  compounds,  of  which  only  a  small  number  have  been 
mentioned,  can  only  be  explained  with  great  difficulty,  and  in  many 
cases  are  quite  inexplicable,  by  the  above-mentioned  theories  of 
Blomstrand  and  Friedheim. 

3.  Structural  formulae  are  of  special  value  when  definite  character- 
istics of  the  substances  they  represent  can  be  deduced  from  them.  In 
this  direction  the  structural  formulae  proposed  by  Friedheim  have  not 
been  of  much  service.  For  instance,  the  compounds98 

2  R20  -  V205  •  4  WO,,  and 
4  R20  •  3  V205  •  12  W03, 

which  are  formed  by  the  action  of  vanadic  acid  on  potassium,  sodium  or 
ammonium  paratungstate,  are  chiefly  distinguished  from  each  other 
by  their  characteristic  behaviour  towards  acids.  Compounds  of  the 
type 

2  R2O  •  V2O5  •  4  W03 

liberate  tungstic  acid  on  treatment  with  hydrochloric  acid,  but  no  such 
separation  is  observable,  when  compounds  of  the  type 

4  R20  •  3  V206  •  12  W03 
are  similarly  treated. 

Friedheim  represents  the  structure  of  these  two  series  as  follows  : 

1.  (2R20-     V.O.-  4WO3-Jaq.)li  =  J  H20  •  3  R20  •  1J  V206  •  6  WO, 

2.  (4R2O  •  3  V206- 12  W03  •'  aq.)    J  =  J  H20  •  2  R2O  •  1J  V205  •  6  W03 


ARE  ALUMINOSILICATES  COMPLEX  ACIDS  OR  SALTS?     21 

°<» 


V(OWO2  •  OR)3  0V-  OW02  •  OW02  •  OR 


OV/O  •  W02  •  OR  OV(OW02  •  OW02  •  OR)2 

\OWO2  •  OW02  •  OR 

Yet  from  these  somewhat  complicated  formulae  it  is  impossible  to 
infer  the  different  behaviour  of  these  two  substances  to  acids,  and 
Friedheim  is  again  compelled  to  resort  to  a  molecular  representation.* 
The  compound100 

3  K20  •  P205  •  5  Mo03 

appears  to  be  an  exception.    It  is  regarded  by  Zenker  and  Blomstrand 
as  molecular,  but  as  atomic  by  Friedheim,  who  represents  it  as 

X)Mo02  •  OMo02  •  OK 
OP^-OK 


OP^-OK 

\OMo02  •  OMo02  •  OK 

This  structural  formula  shows  that  one-third  of  the  potassium 
should  behave  differently  from  the  remaining  two-thirds.  This  agrees 
with  the  behaviour  of  this  substance  towards  dilute  nitric  acid,  in 
which  one-third  of  the  potassium  atoms  are  more  easily  separated  than 
the  others.  This  is,  however,  quite  unusual. 

Friedheim  and  his  associates  also  formulated  other  theories  re- 
specting the  complex  acids  and  their  salts.  For  instance,  they  sought 
to  explain  their  formation  by  reference  to  that  of  the  double  salts,101 
but  this  hypothesis  is  by  no  means  free  from  objection.  The  facts 
mentioned  under  h  (p.  16)  in  the  description  of  the  general  character- 
istics of  complex  compounds  are  quite  opposed  to  it,  and  any  attempt 
to  apply  Friedheim's  hypothesis  to  the  chief  members  of  this  group  is 
sure  to  meet  with  many  serious  difficulties  and  contradictions.  How 
is  it  possible,  for  example,  to  use  this  theory  to  explain  the  nature  of 
compounds  containing  a  large  proportion  of  anhydride  such  as  the 
previously  mentioned  silicomolybdate 

2  R20  •  Si02  •  12  Mo03 

or  the  corresponding  silicotungstate  ?     In  such  a  case  it  is  necessary 
to  assume  the  existence  of  purely  hypothetical  molecular  compounds. 

*  Since  the  above  was  written  Friedheim99  has  abandoned  the  use  of  the  formulae 
1  and  2  and  now  uses  the  atomic  arrangement  shown  below. 


22  CRITICAL  REVIEW  OF  EXISTING  THEORIES 

The  free  acids  are  a  source  of  other  difficulties,  for  how  can  the 
constitution  of  the  phosphotungstic  acid 

3  H2O  •  P205  •  24  W03 
be  represented  ? 

Friedheim  suggested  that  such  free  acids  contain  an  anhydride 
with  the  character  of  a  base,  from  which  it  would  follow  that  the  so- 
called  acid  is  really  a  salt.  Thus,  he  regarded  the  compound 

2  H2O  •  P206  •  V206 
as  a  salt  of  phosphoric  acid,102  namely 


0(V02) 
and  an  analogous  compound, 

Na20-P206-2V205, 

from  which  the  first  may  easily  be  prepared,  as  a  double  salt  of  a  vana- 
dium salt  of  phosphoric  acid  and  a  sodium  salt  of  vanadic  acid,  viz. 

R2O  •  P205  •  2  V205  =  R20  •  V2O5  +  V205  •  P206. 
Such  a  classification  is  obviously  confusing  ;  whenever  the  analytical 
results  are  expressed  as  formulae  indicative  of  double  salts,  the  com- 
pounds must  be  similarly  represented,  or  —  if  double  salts  are  excluded 
—  the  formulae  have  another  meaning  and  represent  either  molecular 
compounds,  whose  components  are  hypothetical,  or  —  in  the  case  of 
free  acids  —  compounds  in  which  one  of  the  two  anhydrides  is  regarded 
as  a  base. 

Summary 

In  summarising  the  arguments  for  and  against  these  theories  with 
regard  to  the  constitution  of  the  aluminosilicates,  it  should  be  ob- 
served that  the  sixth  hypothesis  (that  the  aluminosilicates  are  complex 
acids  and  the  salts  of  such  acids)  explains  a  whole  series  of  reactions 
which  are  quite  inexplicable  by  the  other  hypotheses  (with  the  excep- 
tion of  the  "  molecular  compound  "  theory  by  which  "  everything  " 
can  be  explained)  and  that  most  of  the  best-known  chemical  reactions 
involving  aluminosilicates  are  in  agreement  with  it. 

It  is  now  clear  that  : 

1.  The  splitting  off  or  addition  of  Si02  is  a  sign  of  the  formation 
of  complex  anhydrides  and  analogous  compounds. 

2.  The  simultaneous  presence  of  Si02  and  A1203  in  the  products  of 
the  aluminosilicates  and  the  easy  conversion  of  one  aluminosilicate 
into  others  are  comparable  to  the  analogous  reactions  of  phosphotung- 
states,  phosphomolybdates,  etc. 

3.  The  ratio  Si02  :  A12O3  remains  unaltered  in  reactions  involving 
double  decomposition  and  that  no  replacement  of  aluminium  by  ele- 
ments capable  of  forming  oxides  of  the  R"0  or  R'2O  type  has  been 
observed. 

:  <   4.  There  is  a  genetic  relationship  between  all  aluminosilicates,  and 
that  they  can  be  converted  into  each  other. 


THE   ACID   NATURE   OF  ALUMINA  23 

5.  Most  of  the  aluminosilicates  are  convertible  into  stable  com- 
pounds by  the  action  of  geological  forces. 

6.  The  reactions  of  a  geological  nature  are  analogous  for  all  the 
silicates  ;   those  which  contain  no  A12O3,  etc.  (but  are  almost  entirely 
composed  of  SiO  2)  under  atmospheric  influences  form  silicic  hydrates 
(opals),  whilst  the  salts  of  the  complex  aluminosilicic  acids  are,  under 
similar  conditions,  converted  into  the  hydrates  of  the  complex  alumino- 
silicate  radicles  (kaolins). 

7.  Highly  aluminous  aluminosilicates  (sapphirin)  as  well  as  those 
low  in  alumina  (petalite)  are  known  to  exist. 

There  is  also  a  large  number  of  facts  indicative  of  the  acid  character 
of  aluminium  in  the  aluminosilicates,  as  previously  mentioned.  In 
some  highly  aluminous  slags,  salts  of  aluminic  acid  (aluminates)  are 
known  to  be  formed  at  high  temperatures,  and  silica  appears  to  be 
unable  to  displace  the  aluminic  acid  from  these  compounds.103  The 
simultaneous  formation  of  salts  of  silica  and  alumina,  even  in  the 
presence  of  an  excess  of  free  silica,  has  been  observed  ;  this  fact  clearly 
shows  that  aluminium  has  undoubtedly  a  much  stronger  acid  character 
than  silicon.104 

Vernadsky713  has  drawn  special  attention  to  the  following  facts  in 
support  of  the  acid  nature  of  alumina  in  the  aluminosilicates  : 

(a)  The  conditions  in  which  aluminosilicates  are  formed  both  hi 
the  laboratory  and  in  Nature  are  precisely  those  which  are  favourable 
to  the  production  of  aluminates.     The  minerals  of  the  spinel  group 
separate  from  molten  siliceous  masses  at  high  temperatures.    A  separa- 
tion of  aluminates  from  such  fused  materials  can  only  be  explained 
on  the  assumption  that  the  alumina  has  an  acid  character  in  such 
aluminates. 

(b)  The  separation  of  aluminosilicates  at  high  temperatures  is 
accompanied  by  the  formation  of  aluminates  (according  to  the  experi- 
ments of  Vernadsky  and  Moroziewicz  spinels  are  formed). 

(c)  At  much  lower  temperatures  the  action  of  water  or  carbonic 
acid  solution  not  infrequently  results  in  the  decomposition  of  alumino- 
silicates and  the  separation  of  aluminates  (vide  Thugutt)  or  hydrated 
alumina,  with  the  formation,  in  Nature,  of  bauxite  or  hydrargillite. 
All  these  reactions  are  opposed  to  the  conception  that  alumina  plays 
the  part  of  a  base  in  the  aluminosilicates. 

According  to  Zulkowski714  the  acid  nature  of  alumina  in  the 
aluminosilicates  explains  a  fact  which  has  long  been  regarded  as 
paradoxical  by  metallurgists,  viz.  whilst  it  is  found  that  one  molecule 
of  lime  effects  the  slagging  or  fusion  of  one  molecule  of  silica,  it  is  also 
found  that  just  as  much  lime  is  required  when  the  silica  is  combined 
with  alumina.  This  is  incomprehensible  if  alumina  is  regarded  as 
basic,  but  is  readily  understood  if  alumina  plays  the  part  of  an 
acid. 

It  should  also  be  observed  that  Clarke715  has  repeatedly  described 
aluminosilicates  as  possessing  an  acid  character,  and  regards  the 


24  CRITICAL   REVIEW  OF   EXISTING   THEORIES 

tourmalines  as  derivatives  of  an  acid  H14Al5B3Si6031,  the  water  in 
which  may  be  totally  replaced. 

Other  facts  are  available  for  showing  that  silica  when  combined 
with  alumina  behaves  in  a  different  manner  chemically  from  what  it 
does  in  silicates  devoid  of  alumina,  and  that  the  aluminosilicates  may 
rightly  be  regarded  as  "  complexes  "  as  defined  by  Oswald  (p.  16). 
Thus: 

(a)  Hautefeuille105  observed  that  tungstic  anhydride  can  displace 
silicic  acid  from  its  salts  at  900°  whilst  with  aluminosilicates  under 
similar  conditions  the  displaced  material  contains  both  silica  and 
alumina  and  not  silica  alone. 

(b)  By  the  action  of  the  hydrates  of  aluminosilicates  on  carbonates 
at  a  high  temperature,  C02  is  liberated  and  its  place  is  taken  by  both 
alumina  and  silica. 

(c)  Kaolins  and  other  clays  possess  acid  properties  and,  according 
to  Gorgeu  and  Ziemjatschewsky  respectively,  they  can  decompose 
haloid  salts  (KI,  KBr,  etc.)  at  high  and  moderate  temperatures,  with 
the  liberation  of  free  haloid  (acid)  and  the  formation  of  salt-like 
aluminosilicates . 

(d)  In  various  chemical  processes — both  in  Nature  and  in  the  la- 
boratory— substitution-reactions  frequently  occur  in  which  the  alumino- 
silicic  radicle  remains  quite  unaffected.     All  such  reactions  may  be 
expressed  by  the  following  equation  : 

MX  +  MjA  =  MiX  +  MA, 

in  which  X  is  the  anhydride  of  an  acid,  M  and  M1?  two  different  metals, 
and  A  is  the  aluminosilicic  radicle. 

The  authors  who  have  maintained  the  acid  character  of  aluminium 
in  the  aluminosilicates  and  who  have  recognised  the  existence  of  com- 
plex aluminosilicic  acid  in  some  aluminosilicates  have  already  been 
mentioned  in  the  historical  section  of  this  volume.  One  of  these — 
Zulkowski — states  :  "  I  have  .  .  .  also  shown  that  alumina  possesses 
the  previously  anticipated  characteristic  of  forming  compounds  which 
are  not  salts  in  the  ordinary  meaning  of  this  word,  but  which  must 
be  regarded  as  aluminosilicic  acids,  and  that  these  acids  must  occur 
in  certain  aluminous  slags  and  glazes." 

There  are,  however,  some  objections  to  the  hypotheses  under  dis- 
cussion : 

(a)  Although  in  most  chemical  reactions,  the  aluminosilicates 
behave  in  accordance  with  the  sixth  hypothesis,  there  are  others 
which  are,  at  present,  inexplicable  or  are  in  direct  contradiction  to  it, 
as  the  following  examples  will  show  : 

1.  If  the  aluminosilicate  known  as  andesite106, 

CaO  •  Na20  •  2  A1203  •  8  Si02, 
is  regarded  as  a  salt  of  an  aluminosilicic  acid, 

2  H80  •  2  A1203  •  8  Si02, 


ARE  ALUMINOSILICATES  COMPLEX  ACIDS  OR  SALTS?     25 

it  is  easy  to  understand  the  formation  of  analcime  from  andesite  by 
treatment  with  Na2C03,  which,  according  to  Lemberg,  produces  the 

compound 

2  Na20  •  2  A1203  •  8  Si02  (Analcime). 

It  is,  however,  difficult  to  see  why  the  same  chemist  could  not  repro- 
duce andesite  from  analcime  by  means  of  CaCl2.  The  chief  product 
in  the  latter  case  appears  to  be 

2  CaO  •  2  A1203  •  8  Si02. 

2.  By  investigating  the  behaviour  of  the  compound 

Na20  -  A1203  •  2  Si02  (Nepheline) 

towards  gaseous  hydrochloric  acid  and  silver  salts,  P.  Silber107  has 
shown  that  only  one-third  of  the  sodium  is  given  up  to  gaseous  hydro- 
chloric acid  or  is  replaceable  by  silver,  the  remainder  of  the  sodium 
being  quite  unaffected.  Yet  if  the  formula  of  the  complex  alumino- 

silicic  acid  is 

H20  •  A1203  •  2  Si02, 

the  sodium  atoms,  having  replaced  the  whole  of  the  hydrogen,  must 
behave  uniformly  ! 

3.  If  the  sixth  hypothesis — that  the  whole  of  the  aluminium  is  in 
the  form  of  an  acid — is  accepted,  it  follows  that  all  the  aluminium 
atoms  must  behave  similarly  to  chemical  agents.     St.  J.  Thugutt108 
has,  however,  experimentally  proved  the  exact  opposite  in  a  series  of 
aluminosilicates,  and  has  found  that  one-third  of  the  aluminium  be- 
haves differently  from  the  remainder.    For  example,  sodium  nepheline 

4  (Na20  •  A1203  •  2  Si02)  •  5  H2O, 

on  prolonged  digestion  at  200°  with  2  per  cent,  potassium  carbonate 
solution,  one-third  of  the  alumina  passes  into  solution  in  the  form  of 
sodium  aluminate  and  a  residue  of  potassium  natrolite, 

K20  •  A1203  •  3  Si02  aq., 
remains,  according  to  the  following  equation  : 

3  (4  Na2Al2Si208  •  5  H20)  +  8  K2C03  +  9  H20 
=  8  Na2C03  +  8  (K2Al2Si3010  +  3  H20)  +  4  Na2Al2O4. 
Thugutt  has  also  experimentally  proved  this  property  of  aluminium 
in  the  kaolins,  and  in  a  series  of  sodalites  or  sodium  nepheline  hydrates 
in  which  a  portion  of  the  "  water  of  crystallisation  "  is  replaced  by 
several  salts  such  as  NaCl,  Na2S04,  Na2C03,  etc. 

(b)  The  precise  meaning  of  the  term  "  complex  acids  "  is  by  no 
means  perfectly  clear.    As  has  been  shown  in  the  previous  pages,  all 
existing  theories  concerning  the  constitution  of  these  compounds  are 
only  applicable  to  a  comparatively  small  number  of  these  substances 
and  are  not,  in  other  ways,  quite  free  from  objection.     Hence,  the 
hypothesis  that  the  aluminosilicates  are  complex  acids  and  salts  gives 
but  little  information  concerning  their  "  constitution  "  in  the  true 
meaning  of  this  word. 

(c)  A  theory  is  only  of  value  if,  by  its  means,  a  large  number  of 


26  CRITICAL  REVIEW  OF  EXISTING  THEORIES 

facts  can  be  arranged  systematically.  As  there  can  be  no  doubt,  in 
the  present  state  of  our  knowledge  of  the  chemical  nature  of  the 
aluminosilicates,  that  a  genetic  relationship  exists  between  the  com- 
pounds in  this  group — this  being  in  agreement  with  the  sixth  hypo- 
thesis— a  general  systematic  arrangement  in  the  sense  of  the  sixth 
hypothesis  must  be  possible,  e.g.  one  based  on  the  composition  of  the 
complex  anhydrides.  If,  however,  an  attempt  is  made  to  apply  this 
arrangement  to  all  the  aluminosilicates — including  the  felspars,  micas, 
clintonites,  scapolites,  orthochlorites,  etc. — a  very  large  number  of 
hypothetical  anhydrides  is  involved ;  many  of  these  are  of  a  complex 
composition  and  their  existence  has  not,  so  far,  been  proved. 

Vernadsky 109  has  actually  drawn  up  a  scheme  of  classification  based 
on  chemical  properties,  but  he  only  applied  it  to  a  relatively  small 
number  of  compounds  and  made  no  attempt  to  arrange  the  micas, 
felspars,  clintonites  and  other  aluminosilicates  in  a  similar  manner, 
as  he  realised  the  impossibility  of  a  complete  classification  on  such  a 
basis. 

Hence,  although  the  sixth  hypothesis  agrees  the  best  with  the  facts 
of  all  the  theories  mentioned,  there  are  several  objections  to  it,  and 
these  must  not  be  under-estimated. 

Consequences  which  follow  from  the  previous  Theories 

A  number  of  facts  may  now  be  mentioned  which  have  a  character- 
istic relation  to  the  theories  concerning  the  aluminosilicates  and  may 
be  regarded  as  "  consequences  "  of  them. 

A.  The  idea  that  the  constitution  of  the  aluminosilicates  cannot 
be  expressed  in  the  light  of  the  previous  theories  has  often  led  the 
various  investigators  to  formulate  different  theories  in  which  no  atten- 
tion was  paid  to  the  chemical  properties  of  the  aluminates.  Amongst 
these  are  the  so-called  "mixture  theories  "  of  micas,110  scapolites,111 
tourmalines,112  etc.  The  various  investigators  differ  greatly  in  what 
they  consider  to  be  the  components  of  the  mixtures  ;  these  are,  in 
most  cases,  only  hypothetical  and  are  often  of  such  widely  different 
chemical  composition  that  they  can  scarcely  be  described  as  isomorph- 
ous  in  the  strict  meaning  of  this  term.  It  is,  therefore,  impossible  to 
state  the  constituents  of  a  "mixture"  without  knowing  precisely 
what  a  given  investigator  means  by  the  terms  he  uses  for  such  con- 
stituents. 

In  this  connection  it  is  interesting  to  note  that  Clarke113  has 
recently  suggested  that  the  orthosilicates  can  form  "  isomorphous  " 
mixtures  with  tri-silicates  and  other  poly-silicates.  The  acceptance  of 
this  led  Clarke  to  formulae  which  appear  to  be  very  improbable.  For 
instance,  he  suggests  for  Zinnwaldite114  the  following  formulae  :* 

1.  Al244Fl167K224Si224H116(AlFl2)2o(Si308)156(SiO4)3ofl) 

2.  Al239Fl186Si218H112(AlFl2)209(Si308)151(Si04)312. 

*  Zinnwaldite  is  usually  considered  to  be  an  iron-lithium  silicate  and  not  a 
fluorine  compound. — A.  B.  S. 


SOME   CONSEQUENCES   OF   CURRENT   THEORIES        27 

By  using  the  symbol  X  for  both  Si04  and  Si3O8  and  the  symbol 
R  for  K,  Li,  H  and  A1F2,  he  obtained  the  following  constitutional 

formulae  i 

1.  56  (A1X3F13R3)  +  53  (A1X3R9)  +  45  (A13X3R3), 

2.  62  (A1X3F13R3)  +  49  (A1X3R8)  +  43  (A13X3R3). 

Re-calculating  an  analysis  of  cryophillite115  made  by  Riggs,  Clarke 
obtained  the  following  highly  complex  formula  : 

Al186Fl84K256Li324H146(AlFl2)187(Si308)227(Si04)1855 
and  expresses  this  as  : 

31  (A1X3F13R3)  +  81  (A1X3R9)  -f  25  (A1X3R3). 

Clarke  has  also  obtained  similarly  complex  formulae  for  other 
silicates  including  stilbite,  chabasite,  heulandite,116  etc.  and  has  en- 
deavoured to  explain  these  in  an  analogous  manner. 

B.  A  somewhat  large  amount  of  caprice  is  observed  in  studying  the 
representations  of  the  constitution  of  some  silicates.    Each  investigator 
selects  that  arrangement  which  he  considers  to  be  the  most  convenient 
for  his  own  use  and  it  is,  therefore,  very  difficult  for  anyone  else  to  accept 
any  particular  theory.    The  current  hypotheses  respecting  the  con- 
stitutions of  the  two  following  aluminosilicates  : 

(a)  K20  •  A1203  •  2  SiO2  (Phakelite)  and 

(b)  K20  •  A1203  •  6  Si02  (Orthoclase), 

are  typical  instances. 

(a)  The  Constitution  of  Phakelite 

P.  Groth117  regards  this  compound  as  a  simple,  normal  salt  of 

orthosilicic  acid,  viz. : 

Si  s=  03  i  Al 

\OK. 

C.  Rammelsberg118  represents  it  molecularly  as  : 

K4Si04  •  Al4Si3012. 

S.  J.  Thugutt119  also  represents  it  molecularly,  but  with  other  com- 
ponents, viz. : 

2  K2Al2Si3010  •  K2A1204. 

Vernadsky120  considers  it  as  a  salt  of  an  aluminosilicic  acid  : 
H20  •  A1203  •  2  Si02. 

(b)  The  Constitution  of  Potash  felspar  (orthoclase) 

As  a  product  of  pseudomorphic  processes  Tschermak  regards  ortho- 
clase molecularly  as  : 

K20-Al203(Si02)4-(Si02)2. 

Tschermak121  represents  it  atomically  : 

OK 


CRITICAL  REVIEW  OF  EXISTING   THEORIES 

P.  Groth122  assigns  it  to  the  following  constitution  : 
Si  _  0  —  Al 


o  o 


0-K 

Clarke123  prefers  : 

/[Si308]  E=  K3 

AlAsiaO,]  =  Al 

\[SiiO.]  =  Al 

S.  J.  Thugutt124,  as  the  result  of  experiments,  uses  the  following 
constitutional  formula  : 

2  K2Al2Si3010  •  K2A1204  •  12  Si02. 

Rammelsberg  considers  it  to  be  a  multiple  salt   (double  salt) 
analogous  to  albite  and  writes  the  formula  : 

/K2Si205  +  Al2Si6015^ 
\K2Si03   +  Al2Si309J 

Wartha  represents  the  structural  formula  of  orthoclase  as  : 


Vernadsky125  regards  orthoclase  as  a  complex  salt  of  an  acid 

H20  •  A1203  •  6  Si02, 
and  writes  its  structural  formula  : 

OK 

il 

/\ 

tt 
o  o 


Zulkowski714  regards  felspar  as  a  salt  of  a  complex  aluminosilicic 
acid  and  gives  it  the  following  formula  : 

Al  —  0  •  SiO  •  0  •  SiO  •  0  •  SiO  •  OK 

/\ 

0  O 

V 

Al  —  0  •  SiO  •  0  •  SiO  •  0  •  SiO  •  OK 

Attention  may  also  be  called  to  the  suggestion  of  Haushofer716,  who, 
in  order  to  show  the  genetic  relationship  of  the  felspars  with  granites 


RESULT   OF   CRITICAL   REVIEW  29 

and  micas,  attributed  the  following  constitutional  formula  to  ortho- 
clase  : 

O 

0  =  Si  —  0  —  Si  —  O  —  AXSi  —  OK 


A 

0  =  Si  —  0  —  Si  —  O  —  Al/°\Si  —  OK 
O  ° 

Mellor  and  Holdcroft708  regard  orthoclase  as  a  salt  of  an  alumino- 
hexa-silicic  acid  and  suggest  the  formula  : 

O  =  Si  —  O\        /O  —  Si  =  0 
O<C  >Alt\  1=^=0 

0  =  Si  —  O/  A    X0  —  Si  =  O 


O 

0  =  Si     Si  =  0 
OK   OK 

C.  Some  aluminosilicates,  viewed  in  the  light  of  existing  theories, 
are  extremely  puzzling  even  when  they  are  not  highly  complex.    The 
formula  of  ardennite,126 

10  MnO  •  V205  •  5  A1203  •  10  Si02  •  5  H20, 

is  thus  described  by  Groth  :  "  This  formula — though  based  on  only  a 
few  analyses — indicates  such  a  complex  structure  that  it  is  highly 
probable  that  further  investigation  will  lead  to  its  simplification." 

This  declaration  was  made  by  Groth  because  he  was  not  in  a  posi- 
tion to  find  a  simpler  formula  which  would  agree  with  the  theories 
mentioned. 

D.  Another  consequence  of  the  current  theories  is  that  in  many 
experimental  researches  no  analyses  are  calculated  into  formulae,  the 
usual  view  being  that  the  substances  are  not  true  compounds,  but 
"  isomorphous  mixtures."    It  is  clear  that  many  interesting  character- 
istics are   overlooked   in   the   absence   of   formulae.    Lemberg127   is 
typical  of  many  other  investigators  who  do  not  express  their  results 
by  means  of  formulae. 

The  Result  of  the  Critical  Examination  and  the  Possibility  that  the 
Objections  raised  to  the  Sixth  Hypothesis  are  unreal 

A  critical  examination  (pp.  8-26)  has  shown  that  the  alumino- 
silicates and  such  complex  compounds  as  the  silicotungstates,  the 
phosphotungstates,  etc.  are  closely  related  substances  ;  it  has  shown, 
moreover  that,  in  all  probability,  both  these  groups  of  compounds 
may  be  regarded  as  members  of  a  single  class. 

With  regard  to  their  constitution,  this  examination  only  shows  that 


30          A  HYPOTHESIS   RESPECTING   ATOMIC   BONDS 

the  structure  of  every  compound  is  not  yet  known.  The  previous 
theories  on  the  constitution  of  the  aluminosilicates  cannot  be  regarded 
as  satisfactory,  as  notable  objections  can  be  raised  against  each,  and 
none  of  them  is  capable  of  logical  application  to  the  interpretation  of 
the  chemical  nature  of  the  aluminosilicates  as  a  whole,  nor  can  any  of 
them  be  used  for  a  systematic  classification.  At  the  same  time,  it 
should  be  noted  that  the  conception  of  the  aluminosilicates  as  complex 
acids  or  salts  agrees  well  with  the  facts. 

So  long  as  no  better  theories  are  available  the  sixth  hypothesis  must 
claim  precedence,  in  spite  of  the  objections  to  it  already  indicated. 

It  is,  however,  not  improbable  that  these  objections  are  only 
apparent  and  that  they  would  be  completely  overcome  if  the  manner 
in  which  the  atoms  in  the  anhydrides  of  the  aluminosilicates  are  bound 
to  each  other  were  known.  By  the  use  of  a  suitable  hypothesis  for  the 
structure  of  these  anhydrides,  a  confirmation  of  this  statement  may  be 
found.  The  authors  of  this  present  volume  have  actually  formulated 
such  a  hypothesis,  and  its  nature  and  the  conclusions  which  may  be 
drawn  from  it  form  the  subject-matter  of  the  following  pages.* 


Section  III 

A  Hypothesis  to  show  the  Bonding  of  the  Atoms  in  the 

Aluminosilicates  and  related  Chemical  Compounds 
i 

A.     Two  New  Radicals  —  Hexite  and  Pentite 

1.  Hexite 

IF  six  molecules  of  Si(OH)4  unite  together,  splitting  off  water  and 
retaining  the  quadrivalency  of  the  silicon  so  as  to  form  a  "closed 
ring,"  the  following  constitutional  formula  is  produced  : 

(OH), 

Ji" 


2(OH)=S/ 
0 
,(OH)=Si)  Si  =  (OH) 


\/ 
Si 

(OH)2 

Formula  I. 

*  In  sections  I  and  II  the  authors  have  followed  Vernadsky  :  "  Uber  die  Gruppe 
des  Sillimanits  und  die  Rolle  der  Tonerde  in  den  Silicaten  "  (Bull,  der  Moskauer  Gesdl- 
schaft  der  Naturforscher,  1891,  1,  1-100). 


TWO   NEW  RADICALS  31 

If  six  molecules  of  water  are  split  off  from  formula  I,  the  constitu- 
tion shown  in  formula  II  is  produced  : 

0 
II 

Si 

/\ 

O     0 

0  =  Sif7          ^jSi  =  0 
O  O 

0  =  Sil  ISi  =  0 

O     0 

\/ 
Si 

& 

Formula  II. 

Formula  I  is  shown  in  abbreviated  form  by  means  of  the  following 
symbols  : 

(OH),  H2 

II  II  II 


.(OHj-^-fOH), 


(OH),  H:, 

Formula  III.  Formula  IV.  Formula  V. 

And  formula  II  by  the  symbol : 

|  Si  | 

Formula  VI. 

In  the  following  pages  these  abbreviated  forms  will  be  used  in 
place  of  formulae  I  and  II. 

If  six  molecules  Al(OH)3  unite  together  to  form  a  "ring"  after 
losing  six  molecules  H2O,  but  retaining  the  tri valency  of  the  aluminium, 
formula  VII  is  obtained  : 

Al  — OH 


HO  — A3,7          ^Al— OH 
O 

HO—  AL  /Al  — OH 

O     0 

\/ 

Al  — OH 

Formula  VII. 


32  TWO   NEW   RADICALS 

By  the  removal  of  three  molecules  of  H20  from  formula  VII  the 
anhydride  3  A12O3  is  produced. 

Instead  of  formula  VII,  the  symbols 


OH 

HO  —  /\  —  OH 
HO  —  lJ  —  OH 


or 


H 

I 

H—  /\  —  H 

Al 


O 


H  — 


—  H 


or 


H 

Formula  VIII. 


Formula  IX. 


X 


Formula  X. 


may  be  used,  the  atomic  complex  3A1203  being  then  represented  by 

\ 


Formula  XI. 

The  radicals  indicated  by  the  symbols  in  formulae  VI  and  XI  are 
termed  "Hexite,"  6  Si02  being  known  as  "Silicon  hexite "  and 
3  A12O3  as  "  Aluminium  hexite." 

For  Silicon  hexite  and  Aluminium  hexite  the  respective  symbols 

Si  and  Al 
will  also  be  employed. 

The  hydrates  of  these  hexites — such  as  : 

6  H20  •  6  Si02, 
4  H2O  •  6  Si02, 
3  H20  •  3  A12OS,  etc., 

are  termed  "  Hydrohexites." 


II.   Pentite 

If  five  molecules  of  Si(OH)4  or  A1(OH)3  form  "  rings  "  in  a  manner 
similar  to  hexite,  the  following  structural  formulae  are  produced  : 


(OH),  (OH), 

II 


H2H2 


Si  ^>=(OH) 

1  1 
H2H2 

= 

Si>= 

)H),  (OH), 

II 

formula  XII. 

Formula  XIII. 

Formula  XIV. 

OH  OH 

H  H 

OH  OH 

1  i  + 

|AI)>— 

TT   TT 

&- 

Formula  XV. 

Formula  XVI. 

Formula  XVII. 

A   HYPOTHESIS  RESPECTING   ATOMIC   BONDS          33 

If  the  appropriate  number  of  H20  molecules  is  removed  the  anhy- 
drides 


Formula  XVIII.       Formula  XIX. 

are  obtained. 

The  meaning  of  the  symbols  and  formulae  XII-XIX  is  clear  from 
the  statement  made  with  regard  to  hexite  ;  in  addition,  the  sign  -f  in 
formulae  XV,  XVI,  etc.  indicates  that  an  even  number  of  these 
radicles  must  be  present,  as  such  an  expression  as  \  (5  A12O3)  (Formula 
XIX)  is  impossible  with  existing  conceptions  of  molecules. 

The  ring-forming  polymerisation-products  represented  by  formulae 
XVIII  and  XIX  are  termed  "  Pentite,"  that  corresponding  to  Si(OH)4 
being  referred  to  as  "  Silicon  pentite,"  that  corresponding  to  A1(OH)3 
as  "  Aluminium  pentite,"  and  the  hydrates  : 

5  H2O  •  5  SiO,, 

3  H20  •  5  SiO2, 
J  (5  H20  •  5  A1203),  etc., 
as  "  Hydropentites." 

The  pentites  of  silicon  and  aluminium  will  be  indicated  by  the 
symbols  : 

Si  and  Al, 
respectively. 

B.  The  Representation  of  the  Chemical  Structure  of  the  Complex  Alumino- 
silicic  acids  and  their  Anhydrides  by  means  of  the  Silicon  and  Aluminium 
Pentites  and  Hexites. 

The  silicon  and  aluminium  hexites  and  pentites  just  mentioned, 
provide  the  "  building  stones  "  or  nuclei  for  the  acids  and  anhydrides 
under  consideration.  With  their  aid  the  mode  of  formation  of  the  acids 
appears  to  be  in  accordance  with  the  following  rules  : 

(a)  The  hydrohexites  or  hydropentites  of  aluminium  unite  with 
those  of  silica  or  vice  versa,  the  two  neighbouring  hydroxyl  groups  in 
the  or^Ao-position  in  these  rings  splitting  off  the  elements  of  water, 
two  other  OH-groups,  also  in  the  ortho-position  in  the  silicon  ring, 
losing  their  hydrogen  atom  and  forming  free  H2O. 

By  this  means  : 

1.  From  one  aluminium  hydrohexite  and  two  silicon  hydrohexites, 
viz.  from  3H20  -  3A12O3  and  6H2O  •  6SiO2,  is  obtained  the  formula  : 


(OH),        OH          (OH)2 
This  may  be  expressed  in  four  abbreviated  forms  : 


34     STRUCTURAL  FORMULAE  FOR  ALUMINOSILICIC  ACIDS 


(OH)2      OH      (OH), 
It  I 


(OH),= 
(OH)2= 


=  (OH)2 
=(OH). 


(OH)2      OH      (OH)2 


<y) 

H     i     H 

(8)  H°18(Si  •  Al  •  Si). 

2.  From  a  silicon  hydrohexite  (3H20  •  6Si02)  and  two  aluminium 
hydrohexites  (3H20  •  3A1203)  is  obtained  the  formula  : 

OH  OH  OH 

r_/  ' 


OH- 


or  the  symbols  : 


in        in        OH 

OH  OH  OH 


OH  OH  OH 


H    H    H 

I      I      I 
H—  /\/\/\_  H 


A 


(7) 


l| 


Al  ]  Si  |  Al|™ 

\/\/\/~ 
I      I      I 

H°10(A1  •  Si  •  Al). 


STRUCTURAL  FORMULAE  FOR  ALUMINOSILICIC  ACIDS     35 

3.  From  one  aluminium  hydrohexite   (3H20  •  3A1203)  and  two 
silicon  hydropentites  (5H2O  •  5Si02)  are  obtained  the  symbols  : 


SiAl 
\ 

08)  H°2(Si  •  Al  •  Si), 

which  need  no  further  explanation. 

From  (a)  it  follows  that  each  aluminium  hydrohexite  can  combine 
with  two  or  at  most  three  silicon  hydrohexites  or  hydropentites,  water 
being  split  off.  The  reverse  is  naturally  the  case  with  the  silicon  hydro- 
hexites ;  the  hydropentites  on  the  contrary  can  obviously  combine 
with,  at  most,  two  hydrohexites. 

(6)  Only  those  types  are  produced,  from  the  radicles  just  men- 
tioned, in  which  the  "  rings  "  or  nuclei  are  distributed  quite  sym- 
metrically. From  this  it  follows  : 

1.  That  such  types  as  : 

Si  •  Al  •  Si,* 
Si  •  Al  -  Si, 

are  completely  excluded  as  they  are  unsymmetrical. 

2.  The  type 

Si-Al 

must  be  doubled.    It  then  yields  two  isomeric  types  : 

Si  •  Al  •  Al  •  Si, 

Al  •  Si  •  Si  •  A  of  which 

(3)  both  ends  must  be  formed  of  absolutely  similar  radicles,  as  : 

Si  •  Al  •  Si, 

Si  •  Al  -  Si  •  Al  •  Si,  etc. 

It  also  follows  that  from  the  type 

Si  •  Al  •  Si 
no  such  isomer  as  : 

Si  •  Si  •  Al 
is  possible. 

(c)  The  types  can  only  have  a  group  of  two  similar  radicles  of  the 
same  elements  in  the  middle  and  not  at  the  ends.  Even  in  the 

*  If  the  symbols  are  doubled  and  the  nuclei  symmetrically  placed  ;  such  doubled 
forms  are  theoretically  possible. 


I 


36     STRUCTURAL  FORMULAE  FOR  ALUMINOSILICIC  ACIDS 


middle  they  cannot  have  more  than  two  similar  radicles  of  the  same 
substance.     The  following  types  are  therefore  excluded  : 

Si  •  Si  •  Al  •  Si  -  Si , 
Si  •  Al  •  Al  •  Al  •  Si, 
Al  •  Al  -  SAi  •  Si  -  Al  -  Al, 
Al  •  Si  •  Si  •  Si  •  Al,  etc. 

From  what  has  been  already  stated  it  will  be  seen  that  the  following 
structural  formulae  are  possible  : 

I       I      II 


1.    ~|  Si  |  Al  |  Al  |  Si  |=  =  H°o  (Si  •  Al '  &  '  Si)  =  10  H20  •  6  A1203  •  12  Si02 


iWY 

_AAAA_        .  A- 

2.  _|  Si  |  Al  |  Al  |  Si  |__  =  H«2  (Si  •  Al  •  Al  •  Si)  =  6  H20  •  6  A120,  -  12  Si02 

I       I       I      I 

n__A/\_i 

3.  =  /  Si  I  Al  |  Al  |  Si  ^>=  =H$6  (Si  •  Al  •  Al  •  Si)=8  H20  •  6  A1203  •  10  Si02 

Tyy-l 


Si  y~  =  HJ0  (Si  •  Al  •  Al  •  Si)=5  H20  •  6  A1203  •  10  Si02 


5.    '    |  Al  |  Si  |  Si  |  Al  |      =  H°6  (Al  •  Si  •  Si  -  M)  =  8  H20  •  6  A1203  •  12  Si02 

~\/\/\/\/ 

I      II      II      I 

I       I 


6.         Al    Si  |  Si   Al  |      =  Hg  (Al  •  Si  •  Si  •  Al)  =  4  H20  •  6  A1203  •  12  Si0 
I       I 


I 

7.       <^A1 1  Si  J  Si 
\~\/\/ 


=  H»a  (Al  •  S"i  •  &  •  Al)  =  6  H20    5  A120,  •  12  SiO, 


STRUCTURAL  FORMULAE  FOR  ALUMINOSILICIC  ACIDS    37 


8. 


Si     Al 


\ 


/     y^x 

=  H°4    Al;-SAi 


12  H20  •  3  A1203  •  18  Si02 


t<k 


9.         Si     Al 


/ 

|   I  Al^-S 

v 


H|     Al^-S     =  3  H2O  •  3  A1,O,  •  18  Si02 


10.     =<      Si 


Al 


—  H° 

—  n-is 


=  9  H20  •  3  A1.0.  •  15  SiO, 


11.    =<     Si 


Al 


H!     Alf-Si    =  3  H20  •  3  A120,  •  15  SiO, 


Al 


Si 


=  H;J  SAi  ^Al)  =  6  HaO  •  6  SiO,  •  9  A1203 

v 


38     STRUCTURAL  FORMULAE  FOR  ALUMINOSILICIC  ACIDS 


13. 


I  /^\ 

=  H«  I  SAi<- Al  I  =  3  H20  •  6  Si02  •  9  A1203 
Al 


6H2O12Si02.15Al20, 


._  Si|Al  Si  | 

II      I      II 

I      II 

=  /\/\/N = 

.  _|  Si  |  Al  |  Si  |  Al  |  Si  L=H5.  (Si-Al-Si-Al-Si)=8  H20  •  6  A1203  •  18  Si02 
~\/\/\/\/\/~ 


Al   Si     =  H%4  (Si  •  Al  •  Si  •  Al-Si) 

/\/==  12  H20  •  6  Al,  03  •  18  Si02 
I      II      I      II 

I      II      I 
/\/\/\/\/V 


17.=<^  Si  I  All  Si  I  All  Si  \==H?2(Si-Al-SAi-Al-Si)=6HaO-6  Al203-16Si02 

— \A/\/ — 

I      II      I 

etc.  etc. 

The  types  produced  exclusively  from  the  hexites  (e.g.  15  and  16) 
are  termed  "  primary  "  or  "  major  types  "  ;  those  which  contain 
both  hexites  and  "  penta  radicles  "  (3,  4,  7,  10,  etc.)  are  known  as 
"  secondary  "  or  "  minor  types." 

Having  now  shown  the  chief  features  of  the  hypothesis  relating  to 
the  bonding  of  the  atoms  in  the  aluminosilicic  acids,  it  is  necessary 
to  ascertain  how  far  the  facts  support  this  new  theory. 

C.   Consequences  which  follow  from  the  " Hexite-Pentite  Theory" 

I 

If  the  aluminosilicates  are  really  free  acids  or  salts,  of  which  the 
anhydrides  can  be  produced  from  aluminium  and  silicon  hexites  and 
pentites  in  accordance  with  certain  laws  or  rules,  it  follows  that  in 
that  class  of  reactions  known  as  "  double  decomposition  "  the  alum- 
inium cannot  be  replaced  by  other  elements,  but  that  the  alumina- 
silica  ratio  must  remain  constant. 


CONSEQUENCES  OF  THE   H.P.  THEORY  39 

Hence  in  reactions  of  this  kind,  involving  the  following  silicates  : 

(a)  6  Na20  •  6  A1203  •  12  SiO2  =  Na12(&  -  Al  -  Al  •  Si), 
(6)  3  Na20  •  3  A1203  •  12  Si02  =  Na6(Si  •  Al  •  Si), 
(c)  3  Na20  •  3  A1203  •  10  Si02  =  Na6(§T-  Al  -  Si), 

only  those  atoms  which  are  outside  the  brackets  (i.e.  the  sodium  atoms) 
can  be  replaced  by  potassium,  magnesium,  calcium,  etc.  No  such 
replacement  can  occur  with  the  aluminium  atoms  and  the  alumina- 
silica  ratio  must  remain  unchanged. 

As  a  matter  of  fact,  no  replacement  of  the  aluminium  by  elements 
which  form  oxides  of  the  R20  or  RO  type  has  yet  been  observed  either 
in  the  so-called  pseudomorphous  processes  or  during  the  course  of 
experimental  researches  in  the  laboratory. 

Lemberg  (see  Appendix,  page  following  Table  IV)  by  treating  an 
artificially  prepared  compound 

0.5  Na2O  •  5  K20  •  6  A1203  •  16  Si02  =  NaK10(Sl  •  Al  -  Si  •  Al  •  Si) 

with  varying  amounts  of  salt-mixtures  (sodium  and  potassium 
chlorides,  potassium  and  magnesium  chlorides,  etc.)  obtained  the 
following  compounds,  all  having  the  general  formula  : 

RnfSi  •  Al  •  Si  •  Al  •  Si), 


1. 

2. 

Na2O 
2Na20 

•    4. 
•    3. 

5K20 
5K2O 

•6 
•6 

A1203  • 
A12O3  • 

16SiO 
16SiO 

2> 

2 

3. 

2 

.5  Na2O 

. 

3K2O 

•6 

Al 

203- 

16 

SiO 

2 

4. 

3Na2O 

•    2. 

5K2O 

•6 

Al 

203- 

16 

SiO 

2 

5. 

3 

.5  Na2O 

• 

2K20 

•6 

Al 

2O3- 

16 

SiO 

2 

6. 

5Na20 

•    0. 

5K20 

•6 

Al 

203- 

16 

SiO 

2 

7. 

1 

.5K20 

. 

4MgO 

•6 

Al 

203- 

16 

SiO 

2 

8. 

2K20 

•    3. 

5MgO 

•6 

A1203  • 

16SiO 

2 

9. 

2 

.5K20 

• 

3MgO 

•6 

Al 

2O3- 

16 

SiO 

2 

10. 

3K2O 

•    2. 

5MgO 

•6 

Al 

203- 

16 

SiO 

2 

11. 

1 

.5K20 

• 

4  CaO 

•6 

Al 

203- 

16 

SiO 

2 

12. 

2K2O 

•    3. 

5  CaO 

•6 

Al 

203- 

16 

SiO 

2 

13. 

2.25  K2O 

•  3.25  CaO 

•6 

Al 

203- 

16 

SiO 

2 

From  all  these  thirteen  compounds  he  could  only  obtain  a  replace- 
ment of  the  atoms  outside  the  brackets  : 

NaK10(ST-  Al-Si-  Al  •  Si), 

and  the  alumina-silica  ratio  remained  constant. 

A  large  number  of  analogous  phenomena  might  be  mentioned,  but 
as  they  all  lead  to  the  same  conclusion,  the  following  will  suffice.  Thus, 
the  silicate 

(0.5  Na20  •  2.5  CaO  •  3  A1203  •  18  Si02  •  17  H20)2 


(     /    \ 
=jNaCa2.5  Al^Sl    •  17  H20 

*   xsV 


40  CONSEQUENCES  OF  THE   H.P.   THEORY 

is  converted  by  a  six  weeks'  treatment  at  100°  with  KC1  (see  Appendix, 
Table  I,  No.  39a)  into  the  compound 

/      /Six 

KSO  •  3  A1S03  •  18  SiO,  •  13  H20  =  K,  Al(-S"i    •  13  H20. 

V      W 

This  potassium  salt  is  converted  by  a  fortnight's  treatment  at 
100°  with  sodium  chloride  solution  into  the  sodium  salt  (see  Appen- 
dix, Table  I,  No.  39b) 

/        Six 
3  Na20  •  3  A1203  •  18  Si02  •  16  H2O  =  Na6  Al^-Si    .  16  H20. 

V     \Y 
The  potassium  salt 

k 

•  HS0 


3  K20  •  3  AlaO,  •  18  SiOa  •  H20  =  K,          - 

v   x 

after  a  week's  treatment  at  100°  with  sodium  chloride  solution  is  con- 
verted into  the  sodium  salt  (see  Appendix,  Table  I,  No.  39f  ) 


3  Na20  •  3  A1203  •  18  SiO2  -  8  H20  =  Na 


\ 
i  I  •  8  H20. 


The  sodium  salt  (see  Appendix,  Lemberg's  Expts.,  Series  B  (c) 

f         /       .Six 
(3  Na20  -  3  A1203  •  15  Si02  •  7J  H20)2=]  Nae  (  Alf  Si  •  7.5  H20 

[         V      W 

is  converted  after  a  hundred  days'  treatment  with  potassium  chloride 
solution  at  200°  into  the  potassium  salt 

f    /    A 

(3  K20  -  3  A1203  •  15  Si02  •  1J  H20)2  =]  K6  j  Al(-Si  1  •  1J  H20 

[     \  xsv 

and  the  sodium  salt 

3  Na2O  •  3  A1203  •  12  Si02  •  6  H20  =  Na6(Si  •  Al  •  Si)  •  6  H20 

by  a  three  weeks'  treatment  at  100°  with  potassium  chloride  solution 
(see  Appendix,  Table  II,  No.  45a)  into  the  potassium  salt 

3  K20  •  3  A1203  •  12  Si02  •  H20  =  K6(Si  •  Al  •  Si)  •  H20, 
etc.,  etc. 

II 

The  new  hypothesis  implies  a  genetic  relationship  between  the 
various  aluminosilicates  ;  under  suitable  conditions  they  must  be 
mutually  convertible. 


GENETIC   RELATIONSHIPS  41 

Thus  the  silicate 

3  Na20  •  3  A1203  •  12  Si02  =  Na6(Si  •  Al  •  Si), 
can  change  into  the  silicates 

(a)  3  K20  •  3  A1203  •  12  Si02  =  K6(Si  -  Al  •  Si), 

(b)  3  MgO  •  3  A1203  •  12  Si02  =  Mg3(Si  •  Al  •  Si),  and 

(c)  3  CaO  •  3  A1203  •  12  Si02  =  Ca3(Si  •  Al  -  Si), 

the  sodium  being  replaced  by  potassium,  magnesium  or  calcium. 
A  conversion  of  the  substance 

3  Na20  •  3  A1203  •  12  Si02  =  Na.($  •  Al  •  Si), 
into  the  compounds 

(a)  3  Na20  •  3  A1203  •  10  Si02  =  Na6(S~i  •  Al  •  Si), 

(b)  3  Na20  •  6  A1203  •  12  Si02  =  Na6(S_i  -  Al  •  Al  •  Si), 

(c)  3  Na20  •  6  A12O3  •  10  Si02  =  Na6(Si  •  Al  •  Al  •  Si), 

can  be  effected,  in  case  (a)  by  the  conversion  of  the  silicon  hexite  into 
pentite,  in  (b)  through  the  addition  of  an  aluminium  hexite  and  in  (c) 
by  the  simultaneous  transformation  of  the  silicon  hexite  in  (b)  into  the 
corresponding  pentite. 

In  this  manner  a  series  of  changes  in  aluminosilicates  prepared 
artificially  by  Lemberg,  Thugutt  and  others,  and  the  numerous 
naturally  occurring  changes  which  have  been  observed  may  be  clearly 
represented. 

Thus,  Lemberg  (see  Appendix,  Series  B)  : 

1.  By  the  action  of  caustic  soda  solution  of  various  concentrations 
on  the  silicates  : 

(a)  3  Na20  •  3  A1203  -  12  Si02  •  6  H2O  =  Na6(Si  •  Al  •  Si)  •  6  H20, 

(b)  6  Na20  •  6  A12O3  •  12  Si02  =  Na12(Si  •  Al  •  Al  -  Si), 

(c)  6  H20    -6  A1203  •  12  Si02  •  6*H20  =  H12(Si  •  Al  •  Al  •  Si)  •  6  H20, 
obtained,  from  the  (a)  compound,  the  substance 

6  Na2O  •  6  A12O3  •  12  Si02  •  15  H20  =  Na12(SAi  •  Al  •  Al  •  &)  •  15  H20, 

from  (b)  the  substance 

8  Na2O  •  6  A1203  •  12  Si02  •  7  H20  =  Na16(SAi  •  Al  •  Al  •  Si)  •  7  H20, 

and  from  (c)  the  silicates 

6  Na.O  •  6  A1203  •  12  Si02  •  15  H20  =  Na12(Si  •  Al  •  Al  •  &)  •  15  H20  and 
8  Na20  •  6  A1203  •  12  SiO2  -    7  H2O  =  Na^Si  •  Al  •  Al  •  Si)  •    7  H20  ; 

2.  By  treating  the  silicates  (see  Appendix,  Lemberg  Series  B). 
(a)  6  Na20  •  6  A1203  •  12  Si02  =  Na12(Si  •  Al  •  Al  •  Si), 

(6)  3  Na20  •  3  A1203  •  12  Si02  •  6  H2O  =  Na6(SAi  •  Al  •  Si)  •  6  H20,  and 


(c)  3  K20    •  3  A1203  •  18  Si02 


/ 
=  K6( 

v 


42  CONSEQUENCES  OF  THE   H.P.   THEORY 

with  sodium  silicate,  he  obtained  from  (a)  and  (6)  the  substance 

f       /    /SiO 
(3  Na20  •  3  A1203  •  15  Si02  •  7J  H20)2  =  \  Na6  Al— Si  H,  •  15  H20, 

1       V     XSi'J 
and  from  (c)  the  compound 

3  Na20  •  3  A1208  •  12  Si02  •  6  H20  =  Na6(SAi  •  Al  -  Si)  •  6  H2O ; 
3.  From  the  silicate 
(0.5  Na20  •  2.5  CaO  •  3  A1203  •  18  Si02  •  20  H20)2  =- 

by  treatment  for  fifteen  months  at  100°  with  20  per  cent,  sodium 
carbonate  solution  he  obtained  the  compound  (see  Appendix,  Table 
II,  No.  44) 

(/      /Si\ 
Na6  Alf  Si 
V     XSI/ 

and  by  treatment  for  two  months  at  100°  with  a  25  per  cent,  solution  of 
sodium  silicate,  the  substance 

3  Na20  •  3  A1203  - 12  Si02  •  6  H2O  =  Na6(SAi  •  Al  •  Si)  -  6  H20  ; 

4.  From  the  silicates  : 

6  H2O    •  6  A1203  •  12  Si02  •    6  H20  =  H12(Si  •  Al  •  Al  •  Si)  •  6  H2O, 

6  Na2O  •  6  A1203  •  12  Si02  =  Na12(Si  •  Al  •  Al  •  Si), 

6  Na2O  •  6  A12O3  •  18  SiO2  •  12  H20  ,=  Na12(Si  •  Al  -  Si  •  Al  •  Si)  •  12  H20, 

3  Na20  •  3  A12O8  •  12  SiO2  •    6  H20  =  Na6(Si  •  Al  •  Si)  •  6  H20, 

3  K20    •  3  A1203  •  12  SiO2  =  K6(Si  •  Al  •  SAi),  and 


2-15H20, 


3K20    •  3  A1203  •  18  Si02 


.  /  ,  /SK 

=  K6  (Ale-Si  I 

v 


by  treatment  with  a  mixture  of  sodium  chloride  and  caustic  soda 
(see  Appendix,  Lemberg  Series  A)  he  obtained  a  "  sodalite  "  : 

(6  Na2O  •  6  A1203  •  12  Si02)  •  4  NaCl  •  4  H20 

=  Na12(Sll  •  M  •  M  •  Si)  •  4  NaCl  -  4  H20  ; 
5.  From 

3  K20  •  3  A1203  •  12  Si02  =  K6(Si  •  Al  •  Si),  and 


/          \ 
3  K20  •  3  A1203  •  18  Si02  =  K6  Al^Si 

V      \QV 


GENETIC   RELATIONSHIPS  43 

he  obtained  the  "  sodalite  " 

(6  K20  •  6  A1208  •  12  Si02)  •  2  KC1  •  8  H20 

=  K12(Si  -  Al  •  Al  •  Si)  •  2  KC1  •  8  H2O, 
by  treatment  with  a  mixture  of  potassium  chloride  and  caustic  potash. 

6.  From  the  silicates  : 

6  H2O    -6  A1.0,  •  12  SiO2  •    6  H20  =  BC^Si  -  Al  •  Al  •  Si)  •  6  H20, 
6  Na20  •  6  A1203  •  18  Si02  •  12  H20  ==  Na12(Si  •  Al  •  Si  •  Al  •  Si)  -  12  H20, 
3  Na20  •  3  A12O3  •  12  Si02  •    6  H20  =  Na6(Si  •  Al  •  Si)  •  6  H20, 
3K20    •  3  A1203  •  12  Si02  =  K6(Si  •  Al  •  Si), 

3  Na20  •  3  A1203  •  18  SiOa  =  Na6(  Al^S'i 

XS 

A 
3K20    •  3  A1203  •  18  Si02 

and  a  mixture  of  sodium  sulphate  and  caustic  soda  he  obtained  the 
"  sodalite  " 

(6  Na20  •  6  A1203  •  12  Si02)  •  2  Na2S04  •  6  H20 

=  Na12(Si  •  Al  •  Al  •  Si)  •  2  Na2S04  •  6  H20  ; 

7.  From  the  compounds  : 

6  H20    -6  A1203  •  12  Si02  •  6  H20  =  H12(Si  •  Al  •  Al  •  S'i)  •  6  H20, 
6  Na20  •  6  A1203  •  12  Si02  =  Na12(SAi  •  Al  •  Al  •  Si), 

3  Na20  •  3  A1203  •  12  Si02  •  6  H20  =  Na6(SAi  •  Al  •  Si)  •  6  H20, 
3  K20  •  3  A1203  •  12  SiOa  =  K6(Si  •  Al  •  Si), 

3  Na20  •  3  A1203  •  18  Si02 

and  sodium  silicate  he  obtained  the  "  sodalite  " 

(6  Na2O  •  6  A1203  •  12  Si02)  •  2  Na2Si03  •  8  H20 
=  Na12(SAi  -  Al  •  Al  •  Si)  •  2  Na2Si03  •  8  H2O  ; 

8.  From  the  silicates  : 

6  H2O    -6  A1203  •  12  Si02  •  6  H2O  =  H12(Si  •  Al  •  Al  •  Si)  •  6  H20, 
3  Na20  •  3  A1203  •  12  SiO2  •  6  H20  =  Na6(Si  •  Al  •  Si)  •  6  H20, 
3K20    •  3  A1203  •  12  Si02  =  K6(SAi  •  Al  •  Si), 

and  a  mixture  of  sodium  carbonate  and  caustic  soda  he  obtained  the 
"  sodalite  " 

3  (6  Na2O  •  6  A1203  •  12  Si02)  •  4  Na2C03  •  30  H2O 
=  {Na12(Si  •  Al  •  Al  •  Si)},  •  4  Na2CO3  •  30  H20. 


44  CONSEQUENCES  OF  THE   H.P.  THEORY 

From  these  researches  of  Lemberg's  a  genetic  relationship  between 
the  compounds  of  the  five  following  types  : 

1.  SAi  •  Al  •  Si, 

2.  Si  •  Al  •  Al  •  SX 

3.  SAi  •  Al  •  SAi  •  Al  •  Si, 


4.  Al^Si          and 

XSi 

/* 

5.  Al^Si 

Si 
can  be  traced.    This  is  shown  in  the  folio  whig  Table  : 


Table  showing  the  Results  of  Lemberg's  Researches 

(a)  Series  1. 

Si  •  Al .  SAi >  Si  •  Al  •  Al  •  Si. 

(6)  Series  2. 


Si  •  Al  •  Al  •  Si  — 

/ 

SAi  •  Al  •  SAi  — 

—  >-Al\^Si 

Si 

Si 

Al^~Si  

->  SAi  •  Al  -  SAi 

XS'i 

(c)  Series  3. 

/% 

/    o: 


NSi 

~^^SAi-Al-Si 
(d)  Series  4,  5,  6,  7  and  8. 

Si  •  Al  •  Si  •  Al  •  Si  ^—^ 

SAi  •  Al  •  SAi  >  Si  •  Al  •  Ai  •  Si 

Al^Si 

The  experimental  researches  of  Thugutt  produce  analogous  results : 
By  digesting  kaolin139 

(a)    6  H20  •  6  A1208  •  12  SiO.  •  6  H20  =  Hia(SAi  •  Al  •  Al  •  Si)  •  6  H20, 


GENETIC  RELATIONSHIPS  45 

with  2  per  cent,  caustic  potash  solution  at  192-202°  he  obtained  a 

compound 

(6)     6  K20  •  6  A12O3  •  18  Si02  •  18  H20  =  K12(Si  •  M  -  Si  •  Al  •  Si)  - 18  H20 ; 

with  1  per  cent,  caustic  soda  solution,  a  compound 

(c)  6  Na20  •  6  A1203  •  16  Si02  •  10  H20  =  Na12(Si  •  Al  •  S'i  •  Al  -  S7)  -10  H20; 
with  a  mixture  of  caustic  potash  and  potassium  silicate  two  products 

(d)  3  H2O  •  6  Kj.0  •  6  A1203  •  15  Si02  •  6  H20 

=  H6K12(Si  •  Al  •  Si  •  Al  •  Si)  •  6  H20, 

(e)  3  K20  •  3  A1203  •  10  Si02  •  aq.  =  K.(Si  •  Al  •  Si)  aq. 

From  the  above-mentioned  experimental  researches  of  Thugutt  a 
genetic  relationship  may  be  shown  between  the  compounds  of  the 
types  : 

(a)  Si  •  Al  •  Al  •  Si, 

(6)  Si  •  Al  •  Si  •  Al  •  SAi, 

(c)  Si  •  Al  •  Si  -  Al  •  Si, 

(d)  Si  •  Al  •  Si  •  Al  •  Si, 

(e)  Si  •  Al  •  Si. 

From  these  results  it  follows  that  compounds  of  type  (a)  may  be 
converted  into  those  of  type  (&),  (c),  (d),  and  (e). 

Friedel  has,  however,  found  that  compounds  such  as 

SAi  •  Al  •  Al  •  Si 

can  also  be  converted  into  those  of  other  types.  By  treating  muscovite : 
4  H20  •  2  K20  •  6  A12O3  - 12  SiO,  =  H8K4(SAi  •  Al  •  Al  •  Si), 

with    a   mixture   of   potassium    silicate   and   potassium   carbonate, 
Friedel140  obtained  the  compound 

A 


i02  =  K6(^— SAi) 
V    \«fc/ 


3  K20  -  3  A1208-  18  SiO 


Interesting  conversions  of  aluminosilicates  have  also  been  observed 
in  Nature  (pseudomorphous  processes)  ;  these  give  results  analogous 
to  the  experimental  researches  just  mentioned. 

Analcime141 

3  Na2O  •  3  A1203  •  12  Si02  =  Na6(SAi  •  Al  •  Si) 
can  change  into  muscovite 

4  H20  •  2  K20  •  6  Al,08  •  12  Si02  =  ft  j£4(&  •  Al  -  Al  •  Si), 
and  prehnite 

12  CaO  •  6  A120,  •  18  Si02  •  6  H2O  ==  C°a12(Si  •  Al  •  S'i  •  Al  •  Si)  •  6  H2O. 


46  CONSEQUENCES   OF  THE   H.P.   THEORY 

The  silicates  : 

6  Na2O  •  6  A1203  •  12  Si02  (nepheline)  =  Na12(Si  •  Al  •  Al  •  Si), 

3K20    •  3  A1203  •  12  SiOa  (leucite)  =  K6(Si  •  Al  •  Si), 

6  Na30  •  6  A1203  •  12  Si02  •  4  NaCl  (sodalite)        =  Na12(SAi  •  Al  •  Al  •  Si)  • 

4  NaCl, 

3  CaO    •  3  A1203  •  12  Si02  •  12  H20  (laumontite)  =  Ca3(SAi  •  Al  •  Si)  •  12  H20 
may  all  change  into  analcime142 

3  Na20  •  3  A1203  •  12  Si02  =  Na«(Si  -  Al  •  Si). 
In  Nature,  orthoclase143 

/      /SAK 
3  K20  •  3  A1203  •  18  Si02  =  K6  Ai(~Si  I 

v   xsr 

has  also  been  found  to  change  into 

6  H20  •  6  A1203  •  12  Si02  •  6  H20  (kaolin)          =  H12(Si  •  Al  •  Al  •  Si)  -  6  H20 

3  Na20  •  3  A1203  •  12  Si02  (analcime)  =  Na«(Si  •  Al  •  Si) 

6Na20  •  6  A1203  •  18  Si02  •  12  H20  (natrolite)  =  Na12(SAi-Al-SVAl-SAi)-12  H20 

2  H20  •  8  CaO  •  6  A1203  •  12  Si02  (epidote)        =  H4Ca8(Si  •  Al  •  Al  •  S'i) 

3  H20  •  3  A1203  •  12  Si02  (pyrophillite)  =  H6(Si  •  Al  •  Si) 


3  Na20  •  3  A1208  •  18  Si02  (albite)  =  Na 


/       , 
a6|  Al^-Sl  I 


4  H20  •  2  K20  •  6  A1203  •  12  Si02  (muscovite)  =  H8K4(Si  •  Al  •  Al  •  Si). 
Natural  orthoclase144  is  formed  from 
3  CaO    •  3  A1203  •  12  Si02  (laumontite)  =  Ca,(Si  •  Al  •  Si), 
3  Na2O  •  3  A1203  •  12  Si02  (analcime)      =  Na6(Si  •  Al  •  S*i), 
3  K2O    •  3  A1203  •  12  Si02  (leucite)         =  K6(Si  •  Al  •  Si),  and 
12  CaO    •  6  A1203  •  18  Si02  (prehnite)      =  Ca12(Si  •  Al  -  S'i  •  Al  •  S'i). 
Leucite145 

3  K20  •  3  A1208  •  12  Si02  =  ±,(Si  -  Al  •  Si), 
may  be  changed  into  nepheline  : 

6  Na2O  •  6  A1203  •  12  Si02  =  Nal2(Si  •  Al  •  A!  •  Si), 
and  nepheline  into  natrolite  : 

6  Na20  •  6  A1203  -  18  Si02  •  12  H20  =  Na12  (Si  •  Al  •  Si  •  Al  •  Si)  12  H20, 
etc.,  etc. 

Table  showing  the  Natural  Changes  of  the  Aluminosilicates 

1.  Si-Al-Si-   -^^••^•^•^ 

—  *•  Si  •  Al  •  Si  •  Al  •  Si 

2.  Si-Al-Ai-Si-Z^?1'^'8}^'8' 

-  >  Si  •  Al  •  Si 


CHANGES   IN   ALUMINOSILICATES  IN   NATURE         47 

S'i       .sr  Si  •  Al  •  Al  •  S*i 

-Si         > 

"Si         ^  Si  •  Al  •  Si 


3.  Air- Si          >  Si  •  Al  •  SAi  •  Al  •  Si 


4.  Si  -  Al  -  Si  *  A^ 

Si-Al-Sl-Al-Si  "  X$ 

In  consequence  of  the  great  variety  of  silicates,  the  various  products 
formed  from  them  by  the  action  of  the  weather  are  naturally  very 
numerous.  The  members  of  the  felspar  group  are  particularly  dis- 
tinguished by  the  multiplicity  of  their  products.  For  instance, 
potash-felspar  is  converted,  on  weathering,  into  kaolin,  whilst  other 
weather-products  (in  the  formation  of  which  water  as  well  as  air  is 
necessary)  are  muscovite  and  epidote,  with,  less  frequently,  chlorite 
and  zeolite.  Lime  felspar,  on  weathering,  forms  calcareous  zeolite 
(chabasite,  phillippsite,  desmine,  heulandite,  and,  less  frequently, 
laumontite,  skelezite,  etc.).  Soda  felspar  forms  sodic  zeolites  (anal- 
cime,  natrolite,  etc.). 

The  scapolite  minerals,  on  active  weathering,  produce  epidote, 
albite,  biotite  or  muscovite  and,  finally,  kaolin. 

The  tourmalines  are  seldom  affected  by  the  weather,  but  if  so  they 
produce  mica,  chlorite,  etc. 

Some  zeolites  (analcime,  laumontite,  prehnite)  are  converted  into 
felspars  on  exposure  to  the  weather.  The  zeolites  may  also  be  converted 
into  other  zeolites,  as  natrolite  into  prehnite,  analcime  into  natrolite, 
and  chabasite  into  natrolite. 

The  researches  of  Lemberg,  Thugutt,  and  Doelter  have  shown  that 
zeolites  are  easily  converted  into  other  compounds  by  addition  to, 
subtraction  from,  or  replacement  of,  some  of  their  constituents. 

Vernadsky713  has  observed  that  when  granite  is  fused,  aluminosili- 
cates  (e.g.  anorthite)  and  orthosilicates  (e.g.  olivine)  are  produced,  as 
in  the  researches  of  Doelter  and  others.  The  granites  may  also  be 
formed  by  a  reverse  reaction  from  orthosilicates  and  aluminosilicates 
at  a  high  temperature.  Granites  are  also  converted  into  mica,  chlorite, 
minerals  of  the  nepheline  group,  clays,  etc. 

All  these  changes  are  in  accordance  with  the  second  consequence 
of  the  new  hypothesis,  and  the  existence  of  a  genetic  relationship 
between  the  various  aluminosilicates  may  now  be  regarded  as  a  fact 
which  is  established  beyond  dispute.  The  nature  of  this  relationship 
can  also  be  satisfactorily  explained  by  the  proposed  theory. 

Ill 

The  hexite-pentite  hypothesis  renders  possible  a  system  of  com- 
plete chemical  classification  of  the  aluminosilicates  on  the  basis  of 
their  nature  as  complex  anhydrides. 


48  CONSEQUENCES   OF  THE   H.P.  THEORY 

In  order  to  see  how  far  the  consequences  of  accepting  this  theory 
agree  with  the  facts,  it  was  decided  to  calculate  the  formulae  of  a 
large  number  of  the  analyses  of  aluminosilicates  published  in  Hintze's 
"  Handbuch." 

As  some  atoms  or  atomic  groups  can  be  replaced  by  analogous  ones 
— e.g.  the  atoms  K,  Na,  Li  or  Ca,  Mg,  Fe",  or  the  atomic  groups 
A12O3,  Fe203,  Cr203>  Mn203,  etc.,  or  Si02,  Ti02,  etc. — it  was  con- 
sidered desirable  to  make  the  calculation  of  the  formulae  in  such  a 
manner  that,  instead  of  calculating  the  number  of  atoms  of  each 
substance  separately,  the  replaceable  substances  were  taken  together 
in  groups,  thus  : 

Si,Al2(Ca,  Na2,  K2)018  •  6  H20  (desmine),146 

(Si205)2Al(Li,  Na,  H)  (petalite),147 

(Si,  Ti)6012(Fe,  Mn)  (Na,  K),  (neptunite).148 

This  method  of  simplifying  the  calculation  is  due  to  Berzelius149, 
who  recommended  its  use — not  for  all  cases,  but  for  those  in  which  the 
constituents  of  a  substance  bear  no  simple  relation  to  each  other. 

Gerhardt150,  who  undertook  a  re-formulation  of  the  silicates,  did 
not  follow  the  suggestion  of  Berzelius,  but  added  the  various  bases  (such 
as  lime  and  magnesia)  together,  even  when  they  bore  a  simple  relation 
to  each  other.  The  authors  of  the  present  volume  prefer,  however, 
to  adopt  a  grouping  which  more  closely  resembles  that  of  Berzelius. 

By  this  means  it  is  possible  to  convert  the  true  formula  * — the 
interpretation  of  which  is  almost  impossible  on  account  of  the  presence 
of  a  number  of  substances  in  small  quantities — into  a  formula  which 
is  simpler,  and  in  many  cases — but  not  all — to  produce  a  formula  which 
may  be  interpreted  with  ease. 

In  re-arranging  the  formulae,  the  authors  have  endeavoured  to 
keep  as  near  to  the  true  formula  as  possible,  so  as  to  obtain  results  as 
quantitative  as  well  as  merely  qualitative  value.  In  many  instances 
this  led  to  apparently  complex  formulae,  but  even  these  may  be 
represented  atomically. 

Calculations,  by  this  means,  of  the  formulae  from  a  large  number 
of  analyses  of  clintonite,  mica,  scapolite,  orthochlorite,  tourmaline, 
and  felspar,  showed  that  many  compounds  of  this  group  may  be 
arranged  quite  systematically,  according  to  the  type  to  which  they 
belong.  The  results  of  this  calculation  of  the  formulae  from  the 
analytical  figures  are  given  in  the  Appendix.  The  following  types  are 
selected  because  a  large  number  of  the  compounds  previously  men- 
tioned will  be  found  to  fit  them. 

*  The  conversion  of  all  the  analytical  figures  into  molecular  ratios  is  termed  the 
"true  formula"  as  distinct  from  the  approximate  formula  due  to  the  simplification 
proposed. 


CALCULATION   OF  FORMULAE  49 

A.  Types  of  the  Clintonite  Group  * 

I.  R  •  Si  •  R  =6  R2O8  •    6  Si02, 

II.  R-Si-R  =    5R203-    6Si02, 

III.  Si-R-R^-Si        =    6  R203  •  12  SiO2, 

IV.  Si-R-RT-Si        =    5  R203  •  12  Si025 
V.  Si  •  R  •  Si  •  R  •  Si  =    6  R208  •  18  Si02, 

VI.  Si-R -Si -R -Si  =    6  R203  •  16  Si02, 

VII.  R  •  Si  •  R  •  Si  •  R  =    9  R203  •  12  Si02, 

VIII.  R-Si-R-SAi-R  =    8  R2O3  •  12  Si02, 

IX.  Srr-R  =    9R20S-    6Si02, 

* 

xX> 

X.  {  Si(-R  )  t  =15  R208  •  12  Si02. 


B. 

Types  of  the  Mica  Group 

S'i  •  ft  • 

Si 

=  3 

R208- 

12  Si02, 

SI-R- 

Si 

=  3 

R208- 

10  Si02, 

.A 

Rr~Si 

=  3 

Ra08- 

18  Si02, 

Si 

&-Si 

=  3 

R203- 

15  SiOa, 

XSi 

R-Si- 

R 

=  6 

R208- 

6  Si02, 

R  -  SAi  - 

R 

=  5 

R203- 

6  Si02, 

SAi-R- 

R 

-Si 

=  6 

R203- 

12  SiO2, 

Si-R- 

R 

•Si 

=  6 

R2O3- 

10  Si02) 

Si-R- 

R 

•Si 

=  5 

R203- 

12  Si02, 

SAi-R- 

Si 

•  R  •  Si 

=  6 

R203- 

18  Si02, 

Si-R- 

Si 

•R  -Si 

=  6 

R203- 

16  Si02, 

Si-R- 

Si 

•  R  •  SAi 

=  5 

R2O3- 

18  Si02, 

R-Si- 

R 

-Si-R 

=  9 

R203- 

12  Si02, 

I. 
II. 

III. 

IV. 


V. 

VI. 

VII. 

VIII. 

IX. 

X. 

XI. 

XII. 

XIII. 

XIV.  Si  -  R  •  Si  •  R  •  Si  •  R  •  ST=  9  R203  •  20  SiO2. 

*  In  the  Appendix  the  types  are  arranged  in  the  order  of  the  R2O3  present ;  on  the 
present  page  they  are  placed  according  to  their  relationship  with  respect  to  their 
chemical  structure. 


SO  CONSEQUENCES   OF  THE   H.P.   THEORY 

C.  Types  of  the  Scapolite  Group 

I.  SAi  •  R  •  Si  =3  R203  •  12  Si02, 

II.  Si  •  R  •  Si  =3  R203  •  10  Si02, 

III.  Si  •  R  •  R  •  Si  =6  R203  •  12  Si02, 

,       IV.  Si  •  R  •  R  •  SAi  =5  R203  •  12  Si02, 

V.  Si  •  R  •  Si  •  R  •  Si  =6  R203  •  18  Si02, 

VI.  Si  •  R  •  SAi  •  R  •  Si  =6  R203  •  16  Si02, 

VII.  Si  •  R  •  Si  •  R  •  Si  =5  R203  •  18  Si02, 

VIII.  Si  •  R  •  Si  •  Si  •  R  •  Si  =6  R203  •  22  Si02, 

IX.  Si  •  R  •  Si  •  Si  •  R  •  Si  =5  R203  •  22  Si02, 

X.  Si-R-Sl-R-Si-R-Sl=9  R203  •  20  Si02, 

XI.  R^-Si  =  3  R203  •  15  Si02. 

XSi 

D.  Types  of  the  Orthochlorite  Group 

I.  Si  •  R  •  Si  =3  R203  •  12  Si02, 

II.  Si  •  R  •  Si  =3  R203  •  10  Si02, 

III.  R^Sl  =  3  R203  •  18  Si02, 

XSi 

IV.  R^-Si  =  3  R203  •  15  Si02, 

XSi 

V.  R  •  Si  •  R  =6  R2O3  •    6  Si02, 

VI.  ?'Si*R  =5R203-    6Si02, 

VII.  S'i  •  R  •  R  •  S'i  =6  R203  •  12  Si02, 

VIII.  Si  •  R  •  R  •  Si  =6  R2O3  •  10  Si02, 

IX.  Si  •  R  •  R  •  Si  =5  R203  •  12  Si02, 

X.  S'i  •  R  •  Si  •  R  •  Si  =6  R203  •  18  Si02, 

XL  Si-R-Si-R-Si  =  5  R203  •  18  Si02, 

XII.  Si  •  R  •  S'i  •  R  •  Si  =6  R203  •  16  Si02, 

XIII.  R  •  S'i  •  R  •  Si  •  R  =9  R203  •  12  Si02, 

XIV.  R  •  Si  •  R  •  Si  •  R  =8  R203  •  12  Si02, 
XV.  Si  •  R  •  S'i  •  Si  •  R  •  Si  =  5  R203  •  22  Si02. 

E.  Types  of  the  Tourmaline  Group 

I.  R  •  S'i  •  R  •  Si  •  R  =  9  R203  •  12  Si02, 

II.  R  •  S'i  •  R  •  SAi  •  R  =  8  R203  •  12  Si02, 

III.  R-Si-R  =  5R203-    6Si02. 


DIFFERENTIAL   BEHAVIOUR   OF  ATOMS  51 

F.  Types  of  the  Felspar  Group 

I.  Si  •  R  •  Si  •  Si  •  R  •  Si  =  6  R2O3  •  24  Si02} 

II.  Si  •  R  •  SAi  •  Si  •  R  •  Si  =  6  R203  •  22  Si02, 

III.  Si  •  R  •  Si  •  Si  •  R  •  Si  =  6  R2O3  •  20  Si02, 

IV.  Si  -  R  •  Si  •  Si  •  R  •  Si  =  5  R203  •  24  Si02, 
V.  Si  •  R  •  Si  •  Si  •  R  •  Si  =  5  R203  •  22  Si02. 

A  large  number  of  aluminosilicates  may  be  arranged  according  to 
the  authors'  system  (see  Appendix).  Whether  this  classification  is 
suitable  for  all  aluminosilicates  can  only  be  ascertained  by  means 
of  more  analyses  and  by  calculating  more  formulae. 

IV 

The  structural  formulae  devised  by  the  authors  show  that  the 
aluminium  and  silicon  atoms  in  an  aluminosilicate  do  not  always 
behave  the  same  in  chemical  and  physico-chemical  investigations. 
Under  certain  circumstances  some  of  these  atoms  behave  differently 
from  the  remainder,  and  the  same  is  true  of  the  monovalent  and 
divalent  elements  in  these  compounds. 

It  not  infrequently  happens  that  the  hydroxyl  groups  which  form 
the  "water  of  constitution"  in  the  aluminosilicates  are  replaced  by  the 
halogens  :  fluorine,  and  chlorine.  The  structural  formulae  show  that, 
in  the  latter  case,  halogen  atoms  may  be  united  in  various  ways  in  a 
single  aluminosilicate  and  that  these  atoms  must  produce  different 
chemical  or  physico-chemical  properties  according  to  their  position 
in  the  whole  molecule.  A  few  examples  will  make  this  clearer. 

In  type  I 

I       i 


i     i     i     i 

1.  \  of  the  aluminium, 

2.  J  of  the  silicon, 

3.  J  of  the  base  or  hydroxyl  groups  or  the  substitutes  Cl,  Fl,  etc. 
must  clearly  behave  differently  from  the  other  f . 

In  type  II 

II. 

II      I      I      II 
=/\/\/\/\= 
I|  Si  |  A1|A1   Si 


the  aluminium  and  silicon  must  behave  in  a  manner  analogous  to 
those  in  type  I,  but  J  of  the  base  (or  the  hydroxyl  groups  and  their 
substitutes)  behaves  differently  from  the  remainder. 


52  CONSEQUENCES   OF  THE   H.P.   THEORY 

In  type  III 

ill. 


only  J  of  the  silicon  will  behave  differently  from  the  remainder. 
In  type  IV 

IV. 

_AAA 


YYY" 

1.  J  of  the  aluminium, 

2.  J  of  the  silicon, 

3.  J  of  the  base  (or  the  hydroxyl  groups  or  their  substitutes) 
behave  differently  from  the  rest. 

In  types  V  and  VI 


V. 

I      l      l      I      I 
/\/\/\/\/\ 

"I  Si  |  Al|  Si  |  Al|  Si  |" 

'YYYYY 


VI. 


I   /\/\/\_J 

— <Si  Al|Si|Al|Si 

"YYY" 


1.  J  of  the  aluminium, 

2.  f  of  the  base  (Type  V),  or  f  of  it   (Type  VI)  must  behave 
differently  from  the  rest. 

Some  of  these  interesting  results  are  fully  confirmed  by  experiments 
and  researches  already  published. 

In  compounds  of  type  I,  such  as  kaolin, 

6  H20  •  6  A1203  •  12  Si02  •  6  H20  =  H12(Si  •  Al  •  Al  •  Si)  •  6  H20, 
nepheline  hydrate, 

6  Na2O  •  6  A1203  •  12  Si02  •  aq.  =  Na12(Si  •  Al  •  Al  •  Si)aq., 

and  a  number  of  "  sodalites,"  i.e.  derivatives  of  nepheline  hydrate 
(see  p.  59),  which,  according  to  Thugutt,  are  so  constituted  that  part 
of  their  "  water  of  crystallisation  "  is  replaced  by  a  given  salt  (NaCl, 
Na2SO4,  etc.).  The  author  just  mentioned  reached  precisely  the  same 
conclusions  as  the  authors  of  the  hexite-pentite  theory,  viz.  that  one- 
third  of  the  aluminium  behaves  differently  from  the  remainder. 
Thugutt  therefore  suggests  the  following  constitutional  formulae  : 

2  H2Al2Si3O10  •  H2A12O4  •  3  H20  (kaolin), 

4  (2  Na2Al2Si3Oio  •  Na2Al203)  - 15  H2O  (nepheline). 


STRUCTURE   OF  KAOLINS  AND  EPIDOTES  53 

P.  Silber  (p.  25)  has  shown  that  the  behaviour  of  the  compound  : 
6  Na20  •  6  A1203  •  12  SiOa  (nepheline)  =  Na12(Si  •  Al  •  Al  •  Si) 

of  the  same  type  towards  gaseous  hydrochloric  acid  and  silver  solutions 
indicates  that  J  of  the  sodium  behaves  differently  from  the  remainder, 
and  thus  confirms  the  hexite-pentite  theory. 

The  authors  believe  that  confirmation  of  the  constitution  of  com- 
pounds of  type  II  is  to  be  found  in  a  new  set  of  formulae  for  the 
epidotes  (see  Appendix).  The  minerals  in  this  group  are  chiefly  com- 
pounds of  type  II  with  the  general  formula  : 

2  H20  •  8  CaO  •  6  R203  •  12  Si02  =  H4Ca8(Si  •  R  •  R  -  Si) 
R  =  Al,  Fe. 

The  constancy  of  the  ratio  of  lime  to  "  water  of  constitution  "  in 
these  minerals  makes  it  highly  probable  that  £  of  the  hydroxyl  groups 
in  the  acids  corresponding  to  these  minerals  behaves  differently  from 
the  remainder. 

By  replacing  part  of  the  aluminium  by  Fe'"  in  the  formula 

2  H20  •  8  CaO  •  6  A1203  •  12  Si025 

the  various  epidotes  are  produced  and  no  epidote  has  yet  been  found 
with  a  higher  content  than  is  shown  in  the  formula  (see  Appendix)  : 

2  H20  •  8  CaO  •  2  Fe203  •  4  A1203  •  12  SiOa. 

It  appears  probable  that,  under  the  conditions  under  which 
epidotisation  can  occur  in  Nature,  only  those  aluminium  atoms  which 
are  indicated  by  a  dot  in  the  formula  below  can  be  replaced  by  Fe== 


Si    Al    Al    Si 
\/\./\./\/ 


For  the  prognosis  of  type  III,  Thugutt's  work  on  a  compound  of 
this  type  —  potash  felspar  : 

3  K20  •  3  A1203  -  18  Si02  =  K6 


is  important.  According  to  Thugutt,  this  substance,  on  treatment 
with  2  per  cent,  caustic  potash  solution,  loses  silica  and  forms  other 
compounds  which  are  incapable  of  exact  analysis,  but,  so  far  as  he  has 
ascertained  it,  their  composition  agrees  with  the  theory  formulated 
by  the  authors,  viz.  that  the  constitutional  formula  of  potash  felspar 
(which,  according  to  Thugutt,  is  2  K2Al2Si3010  •  K2A1204  •  12  Si02) 
suggests  that  J  of  the  silicon  behaves  differently  from  the  remainder. 
A  partial  confirmation  of  the  prognosis  of  type  IV  appears  to  be 


54  CONSEQUENCES   OF  THE  H.P.  THEORY 

supplied  by  the  composition  of  the  minerals  known  by  the  general 
name  of  "  topaz."  Calculations  of  the  formulae  of  these  compounds 
from  a  number  of  analyses  (see  Appendix)  showed  that  they  belong, 
in  part,  to  type  IV  and  may  be  represented  by  : 

1.  Si6Al12Fl8026, 

2.  Si6Al12Fl9025.5, 

3.  SieAl12Fl10O25, 

4.  SioAl^Fl^O^.s, 

5.  Si6Al12Fl12O24. 

These  formulae  are  based  on  the  assumption  that  one  atom  of 
oxygen  may  be  replaced  by  two  of  fluorine. 

It  appears  probable  that  the  hydrogen  present  in  these  compounds 
has  been  overlooked. 

If  this  assumption  is  admitted — and  the  presence  of  hydrogen  has 
been  independently  proved  by  (a)  Jannasch  and  Locke128  and  (b) 
Penfield  and  Minor — the  topazes  are  derived  from  the  hydrate  : 

V   ' 

AllSilAl 


I      II      I 
Si«Al12024(OH)12 

The  researches  of  Penfield  and  Minor  showed  that  water  in  a  strongly 
combined  state  is  present  in  the  topazes.  In  an  investigation  of  topaz 
from  Stoneham,  which  contained  0-98  per  cent,  of  water,  the  powder 
lost  only  0-12  per  cent,  at  the  highest  temperature  obtainable  by  means 
of  a  ring-burner  (see  Penfield  and  Minor,  Zeitschr.  f.  Krystallogr.  u. 
Mineral.  1894,  23,  321).  It  is  thus  clear  that  the  water  contained  in 
topaz  may  easily  be  overlooked.  The  investigators  just  quoted  have 
found  that  the  water  is  liberated  quantitatively  on  fusing  a  topaz  with 
sodium  carbonate.  The  correctness  of  the  view  that  topaz  contains 
water  in  the  form  of  OH-groups  is  also  confirmed  by  the  following 
interesting  characteristics  of  topaz  :  the  specific  gravity,  the  double 
refraction,  the  apparent  angle  of  the  optical  axes  (2  e)  and  the  crystallo- 
graphic  axis-ratio,  all  of  which,  according  to  Penfield  and  Minor,  vary 
with  the  proportion  of  hydroxyl  in  the  topaz  molecule. 

Assuming,  with  Jannasch128,  that  the  hydroxyl  groups  in  topaz 
may  be  replaced  by  fluorine,  or  vice  versa,  regarding  the  Stadler  topaz  : 

Fl  Fla  Fl 

I      u      I 


I     Ml        I 

Fl  F12  Fl 


as  the  mother-substance  and  replacing  the  fluorine  in  the  latter  by 
hydroxyl  groups,  the  formulae  of  the  following  theoretically  possible 
topazes  are  obtained  : 


THE   STRUCTURE   OF  TOPAZ   AND   GRANITE  55 

Si6Al12024Fl(OH)11, 
SiflAl12024Fl2(OH)10> 
Si6Al12024Fl3(OH)9, 
Si6Al12024Fl4(OH)8, 


Si6Al12024Fl12. 

In  agreement  with  this  assumption,  it  has  been  found  by  actual 
analysis  that  there  is  a  definite  maximum  proportion  of  fluorine — no 
topaz  being  known  which  contains  a  larger  percentage  than  the  Stadler 
variety.  There  also  appears  to  be  a  minimum,  as  no  topaz  is  known 
which  contains  less  than  eight  atoms  of  fluorine  to  six  atoms  of  silica. 
This  interesting  result  is  most  easily  explained  by  stating  that  fluorine 
atoms  which  are  united  to  silicon,  but  not  to  aluminium  (see  the 
structural  formula  of  the  Stadler  topaz),  are  easily  replaced  by  hydroxyl 
under  natural  conditions,  or  that  J  of  the  fluorine  behaves  differently 
from  the  remainder. 

The  probability  of  the  authors'  structural  formula  for  topaz  is 
also  confirmed  by  the  chemical  investigations  of  Rammelsberg,  who 
observed  that  on  heating  topazes  to  redness,  part  of  the  fluorine 
escapes  as  silicon  fluoride  and  part  as  aluminium  fluoride. 

Further  investigations  must  show  that  the  ratio  of  the  fluorine  lost 
in  the  form  of  silicon  fluoride  to  that  lost  as  aluminium  fluoride  is  1  :  2. 

The  prognoses  of  types  V  and  VI  are  partially  confirmed  by  a 
re-calculation  of  the  analyses  (see  Appendix)  of  a  number  of 
granites129  by  K.  H.  Schnerr. 

This  re-calculation  gives  the  following  formulae  : 

20       jo        90         jo        90  jk  10        90        i  o 

5^2^  90    $      ^      t       90* 

II       I       II       I       II  ^      I       II      I       z 

i°==/\./\./\./\./\=1o  y /\./\./\    » 

r  J  Si  I  R  I  Si  j  R  I  Si  L|0  l0==\Si_|  R  |  Si  |  R  [Si/=1° 

II       i       ll       I       ii  90      i       H       i        90 

9°      1°       9°        1°       9°  10       90        TO         " 

^          2  "  2  "  2  ^  2 

18  RO  •  6  R203  •  18  Si02  16  RO  -  6  R208  •  16  Si02 

A.  B. 

These  agree  with  the  theory  that  J  of  the  aluminium  behaves 
differently  from  the  remainder.  The  aluminium  atoms  indicated  by 
dots  may  be  replaced  by  Fe=  ;  compounds  of  type  A  may  contain  a 
maximum  of  4  Fe2O3. 

Although  Schnerr  refers  to  granites  in  which  the  whole  of  the 

*  It  is  convenient  to  represent  the  atomic  groups 
— OR"\  — O,\ 

>0,         _o>R',        -Or  (r=pl') 


by  2°,  1°  and  £°  respectively  (see  also  p.  166) 


56  CONSEQUENCES  OF  THE   H.P.   THEORY 

aluminium  has  been  replaced  by  iron,  experience  shows  that  the  atoms 
indicated  by  dots  are  the  ones  most  easily  replaceable  by  iron. 

It  happens  that  those  aluminium  atoms  in  the  granites  which  are 
the  most  easily  replaceable  by  iron  are  the  very  ones  which,  in  the 
epidotes,  are  incapable  of  substitution,  and  a  closer  study  of  the 
structural  formulae  of  these  two  groups  of  substances  leads  to  the 
conclusion  that  the  epidotes  are  acid  salts  whilst  the  granites  are  basic 
ones.  The  presence  of  a  base  weakens  the  attraction  between  the 
silicon  and  aluminium  ring  radicles,  and  thereby  facilitates  the 
substitution  of  the  aluminium  by  iron  at  the  points  indicated. 

The  consequences  of  the  authors'  hypotheses  mentioned  in  this 
section  agree  with  the  experimental  results  of  other  investigators. 


From  the  hexite-pentite  hypothesis  it  follows  that  there  must  be  a 
minimum  molecular  weight  for  the  aluminosilicates.  Thus,  the 
formulae  of  the  compounds 

Na20  •  A1203  •  2  Si02, 
Na20  •  A12O3  •  3  Si02, 

must  be  at  least  sextupled,  and  those  of 

Na20  •  A1203  •  6  Si02, 
Na20  •  A1203  •  5  Si02,  and 
Na2O  •  A1203  •  4  Si02, 

must  be  at  least  tripled,  in  order  that  they  may  be  represented  in 
accordance  with  the  new  theory.  How  does  this  agree  with  the  facts  ? 
In  many  cases  the  theoretically  minimum  molecular  weight  may  be 
ascertained  from  an  analysis  of  the  substance  or  from  certain  definite 
considerations.  In  this  connection,  one  of  a  series  of  silicates  : 

/  A 

(a)  0.5  Na2O  •  2.5  CaO  •  3  A1203  •  18  Si02  •  20  H20  =  R6|  Al—  Si  I  •  20  H2O 

V     XSi' 


examined  by  Lemberg  (see  Appendix,  Table  II)  is  interesting. 

By  treating  the  silicate  (a)  with  salt  solutions,  Lemberg  obtained 
the  following  compounds  : 

.A 

I.        3  K20  •  3  A1203  •  18  Si02  •  H20          =  K6|  Ab— 

V     XSi> 

/     A\ 
II.        3  K20  •  3  A1203  •  18  Si02  •  13  H20     =  K6(  Al^-Si  I  •  13  H20, 

V     XSi' 

(/i 
Al(-Si  1  •  8  H20, 
xsV 


CONSTITUTION   OF  THE   MESOLITES  57 

IV.        3  NaaO  •  3  A1203  •  18  Si02  •  16  H20  =  NaJ  Al^-Si  |  •  16  H80. 
By  treating  silicate  (a)  with  alkali  he  obtained 


V.      (3  Na2O  •  3  A1203  •  15  Si02  •  7.5  H20)2 


«     /  *  X_\ 
Na6j  Al^-Si 

\      XSi/ 


and  from  the  latter  and  potassium  chloride  the  substance 


VI.     (3  K20  -  3  A1203  •  15  Si02  •  1.5  H20)2  = 


Kefil^l) 
V     XSi/ 


15  H20, 


3H20. 


In  the  case  of  the  compounds  I,  II,  III,  IV,  and  the  silicate  (a) 
from  which  they  are  derived,  the  minimum  molecular  weight  may  be 
found  from  the  analyses  ;  the  formation  of  compound  V  from  silicate 
(a)  and  of  VI  from  V  are  quite  inexplicable  if  a  smaller  molecular 
weight  than  is  required  by  the  hexite-pentite  theory  is  assumed  for 
compounds  V  and  VI. 

A  second  instance  of  interest  in  this  connection  is  the  mode  of 
formation  of  the  potassium  salt 

3  K20  •  3  A1203  •  12  Si02  •  H20  =  K6(Si  -  Al  -  Si)  •  H20, 
from  the  sodium  salt 

Na20  •  A1203  •  4  Si02  •  2  H20, 

as  observed  by  Lemberg  (see  Appendix,  Table  II).  This  can  only  be 
understood  if  the  molecular  weight  of  the  original  material — the  sodium 
salt — is  tripled ;  the  theoretically  minimum  molecular  weight  is  then 
indicated. 

The  number  of  instances  in  which  the  theoretically  minimum 
molecular  weight  may  be  ascertained  from  analysis  is  somewhat  large, 
as  may  be  seen  from  the  authors'  re-calculation  of  the  formulae  of  a 
large  number  of  silicate  analyses.  From  the  numerous  examples 
available,  the  new  formulae  of  the  mesolites  (see  Appendix)  may  be 
mentioned  here. 

Formulae  of  the  Mesolites 

(a)     2  Na20  •  4  CaO  •  6  A12O3  •  18  Sip,  -15  H20^ 

=  Na4Ca4(Si  •  Al  •  Si  •  M  •  Si)  •  15  H20, 

(6)     (1.5  Na20  •  5.5  CaO  •  6  A1203  •  18  Si02  •  22  H20)2^ 

=  {Na3Ca6.5(Si  •  AL  •  Si  •  Al  •  Si)}2  •  44  H20, 

(c)  (Na20  •  3.5  CaO  •  6  A1203  •  17  Si02  •  15  H/)), 

=  {Na2Ca3.5(Si  •  Al  •  Si  •  Al  •  Si)}2  •  30  H20, 

(d)  (2  Na20  •  3.5  CaO  •  6  A12O3  •  17  Si02  •  15  H20)2 

=  {Na4Ca3.5(Si  •  M  •  Si  •  Al  •  Si)}a  •  30  H20, 


58  CONSEQUENCES  OF  THE   H.P.   THEORY 

(e)     2  Na20  •  4  CaO  •  6  A1203  •  16  Si02  •  12  H20 

=  Na4Ca4(Si  •  Al  •  Si  •  Al  •  Si)  •  12  H20, 
(/)  2  Na20  •  3  CaO  •  6  A1203  •  16  Si02  -15  H20^ 

=  Na4Ca,(Si  •  Al  •  Si  •  Al  •  Si)  •  15  H20, 
(g)  2.5  Na20  •  3  CaO  •  6  A1203  •  16  Si02  •  20  H20 

=  Na§Ca,(Si  •  Al  -  Si  •  Al  •  Si)  •  20  H20, 
(h)  1.5  Na20  •  3  CaO  •  6  A1203  •  15  SiO^  •  18  H.O 

=  Na3Ca3(Si  •  Al  •  Si  •  Al  •  Si)  •  18  H20, 
(*)  2.5  Na20  •  3  CaO  •  6  A1203  •  15  Si02  •  13  H2O 

=  Na5Ca3(Si  -  Al  -  Si  •  Al  •  Si)  •  13  H20. 

In  all  the  above  mesolitic  silicates,  with  the  exception  of  (e), 
analysis  indicates  the  theoretically  minimum  molecular  weight,  and 
there  is  no  need  to  doubt  that  the  real  minimum  agrees  with  the 
theoretical  one,  as  otherwise  the  genetic  relationship  which  is  known 
to  exist  between  these  and  other  members  of  this  group  would  be 
inexplicable. 

It  is,  moreover,  particularly  interesting  to  observe  that  Thugutt130 
has,  by  an  entirely  different  method,  reached  conclusions  regarding 
the  minimum  molecular  weight  of  certain  aluminosilicates  which  agree, 
almost  without  exception,  with  the  authors'  theory.  Thugutt's 
conclusions  are  also  of  special  value  because  they  are  based  on  the 
results  of  actual  experiments.  On  the  basis  of  his  previously  mentioned 
researches,  Thugutt  suggests  the  following  constitutional  formula  : 

2  K2Al2Si3010  •  K2A1204  •  12  Si02 
which  is  equivalent  to : 


3  K2O  •  3  A120,  •  18  Si02    =    Ke( 


•SAi' 
the  following  for  nepheline  hydrate  : 

4  (2  Na2Al2Si3010  •  Na2Al204)  •  15  H20 
corresponding  to : 

12  Na20  •  12  A1203  •  24  Si02  •  15  H20  =  {Na12(Si  •  Al  •  Al  •  Si)}2  •  15  H2O, 
and  the  following  for  potash  mica  : 

(a)    K6H6Al12Si18060 
=  3  K20  •  3  H20  •  6  A1203  •  18  SiO2  =  K6H6(Si  •  Al  •  Si  •  Al  •  Si), 

(6)    K4H8Al12Si18060 
=  2  K20  •  4  H20  •  6  A1203  •  18  Si02  =  K4H8(Si  •  Al  •  Si  •  Al  •  Si). 

In  some  silicates  the  theoretically  minimum  molecular  weight  is 
double  that  found  by  Thugutt.  Thus,  he  attributes  to  potash  nephe- 
line the  formula  : 

2  K2Al2Si3010  •  K2A1204, 


CONSTITUTION   OF  THE   SODALITES  59 

which,  if  doubled,  gives  : 

6  K20  •  6  A1203  •  12  Si02  =  K12(Si  •  Al  •  Al  •  Si). 

The  same  is  true  of  Thugutt's  constitutional  formula  for  potash 
mica  : 

H2K2Al4Si6020  •  H2A1204, 
which,  if  doubled,  gives  : 

2  K20  •  4  H20  •  6  A1203  •  12  Si02  =  K4H8(Si  -  Al  •  Al  •  &). 

Equally  interesting  in  this  connection  are  the  so-called  sodalites.* 
According  to  Lemberg's131  and  Thugutt's132  researches,  these  are  not 
atomic,  but  true  molecular  compounds.  This  view  is  opposed  to  that 
of  other  investigators.  It  is  highly  probable,  from  the  results  of 
Lemberg's  and  Thugutt's  experiments,  that  the  sodalites  are  deriva- 
tives of  the  sodium  nepheline  hydrates,  and  that  they  are  so  constituted 
that  a  portion  of  their  "  water  of  crystallisation  "  appears  to  be 
replaceable  by  various  salts.  If  this  is  really  the  case,  on  decomposition 
they  must  be  capable  of  forming  products  which  are  identical  with 
those  from  sodium  nepheline  hydrate. 

Thugutt's  researches  have  shown  that,  in  reality,  one-third  of  the 
sodium  and  one-third  of  the  alumina  can  be  removed  from  the  sodalite 
in  the  form  of  aluminate  of  potash.  Natrolite  may  be  formed  by  the 
action  of  potassium  carbonate  solution,  chloride  of  sodium  (or  whatever 
salt  may  be  added)  being  set  free.  Thus,  the  blue  chlorosodalite  from 
the  elaolite-syenite  from  Ditro  decomposes  in  accordance  with  the 
equation  : 

3  Na2Al2Si208  -  2  NaCl  +  2  K2C08  +  6  H2O 
=  2  Na2C03  +  2  NaCl  +  2  (K2Al2Si3010  •  3  H20)  +  Na2Al204. 

(Of.  the  analogous  behaviour  of  nepheline  hydrate,  p.  61.)  As  a  result 
of  this  reaction,  Thugutt  considers  that  the  formula  of  chlorosodalite 
should  be  : 

2  Na2Al2Si3010  •  Na2Al204  •  2  NaCl, 

but  as  it  is  a  derivative  of  sodium  nepheline  hydrate,  whose  constitu- 
tional formula  is 

8  Na2Al2Si3O10  •  4  Na2Al204  •  15  H20, 

— this  being  confirmed  by  its  reaction  with  potassium  carbonate — 
Thugutt's  molecular  weight  of  chlorosodalite  should  be  at  least  quad- 
rupled ;  its  constitutional  formula  then  becomes  : 

8  Na2Al2SisO10  •  4  Na2Al2O4  •  8  NaCl. 

If  4  Na2SO4  replaces  the  8  NaCl,  the  constitutional  formula  of  the 
sulphatosodalite  or  norsean  is  obtained  ;  if  the  8  NaCl  is  replaced  by 
4  Na2S  2  that  of  ultramarine  results,  and  so  on.  Thugutt  has  artificially 
prepared  a  large  number  of  analogous  substances  and  has  allotted 
molecular  weights  to  them,  as  shown  in  the  following  Table. 

*  Another  means  of  representing  the  constitutional  formula  of  the  sodalites 
atomically  is  possible  and  is  discussed  in  connection  with  the  ultramarines  (p.  152 
et  seq.). 


60  CONSEQUENCES   OF  THE   H.P.   THEORY 

Thugutt's  Sodalite  Series133 


12 

Na20 

•2 

(6 

A1203 

•  12  Si02) 

•8 

NaCl  •  4  H20, 

12 

Na20 

•  2 

(6 

A1203 

•  12 

Si02) 

•  6 

NaBr, 

12 

Na2O 

•2 

(6 

A1203 

•12 

Si02) 

•6 

Nal  -  6  H2O, 

12 

Na20 

•  2 

(6 

A1203 

•  12 

Si02) 

•  8 

NaC103  •  2  H2O, 

12 

Na20 

•2 

(6 

A1203 

•12 

Si02) 

•  3 

Na20.  B203  •  8  H2O, 

12 

Na20 

•2 

(6 

A1203 

•  12 

Si02) 

•2 

Na20  •  I205.  10  H20, 

12 

Na20 

•  2 

(6 

A1203 

•  12 

Si02) 

•  8 

NaC104  •  4  H20, 

12 

Na20 

•2 

(6 

A1203 

•  12 

Si02> 

•4 

Na2C03  •  12  H20, 

12 

Na2O 

•  2 

(6 

A1203 

•  12 

Si02) 

•3 

Na2C03  •  18  H20, 

12 

Na2O 

•2 

(6 

A1203 

•12 

Si02) 

•  4 

Na2Si03  •  16  H2O, 

12 

Na20 

•2 

(6 

A1203 

•  12  Si02) 

.3 

Na2Si03  •  15  H20, 

12 

NaaO 

•2 

(6 

A1203 

•12 

Si02) 

•4 

Na2S04  •  12  H20, 

12 

Na20 

•2 

(6 

A1203 

•  12 

Si02) 

•3 

Na2S04  •  12  H20, 

12 

Na20 

•2 

(6 

A1203 

•12 

Si02) 

•3 

Na2Cr04  -  15  H2O, 

12 

Na20 

•2 

(6 

A1203 

•  12 

Si02) 

•3 

Na,Se04  •  12  H20, 

12 

Na20 

•2 

(6 

A1203 

•  12 

Si02) 

•3 

Na2Mo04  •  21  H20, 

12 

Na20 

•2 

(6 

A1203 

•  12 

Si02) 

•  Na.2W04  •  13  H20, 

12 

Na20 

•  2 

(6 

A1203 

•  12 

Si02) 

•2 

Na4P805  •  12  H20, 

12 

Na20 

•2 

(6 

A1203 

•  12 

Si02) 

•  8 

NaN03  •  6  H20, 

12 

Na2O 

•2 

(6 

A1203 

•  12 

Si02) 

•  3 

Na20  •  P205  •  18  H20, 

12 

Na2O 

•2 

(6 

A1203 

•  12 

Si02) 

•4 

Na2HP04  •  14  H20, 

12 

Na20 

•  2 

(6 

A1203 

•  12 

Si02) 

•2 

Na4P207  •  14  H20, 

12 

Na20 

•2 

(6 

A1203 

•  12 

Si02) 

•3 

Na20  -  Aso05  -  14  H20, 

12 

Na20 

•2 

(6 

A1203 

•  12 

Si02) 

•  3 

Na2S203  •  9  H20, 

12 

Na2O 

•2 

(6 

A1203 

•  12 

Si02) 

•  8 

NaOH  •  4  H20, 

12 

Na20 

•2 

(6 

A1203 

•  12 

Si02) 

•  6 

Nal  •  9  H20, 

12 

Na2O 

•2 

(6 

A1203 

•  12 

Si02) 

•  8 

HCOONa, 

12 

Na20 

•  2 

(6 

A1203 

•12 

Si02) 

•6 

CH3  •  COONa  •  3  H20, 

12 

Na20 

•  2 

(6 

A1203 

•  12 

Si02) 

•3 

Na2C2O4  •  18  H2O. 

The  minimum  molecular  weight  of  any  member  of  this  series  may 
be  ascertained  from  an  analysis  of  the  substance,  as  in  the  two  follow- 
ing sodalites : — 

12  Na2O  •  2  (6  A1203  •  12  Si02)  •  3  Na20  -  B203  •  8  H20    and 
12  Na2O  •  2  (6  A12O3  •  12  Si02)  •  Na2W04  •  13  H20. 
The  hexite-pentite  theory  formulated  by  the  authors  of  the  present 
volume  gives  the  same  molecular  weight.      Moreover,  if  the  salt- 
content  (in  molecules)  of  a  sodalite  is  represented  by 

m2 

and  the  water- content  (in  molecules)  by 

nH, 

the  constitution  of  these  substances  may  be  ascertained  from  the 
following  formula : — 

{Na12(Si  •  Al  •  Al  •  Si)}2  •  m2  ,  nH. 

For  some  micas,  Thugutt134  suggests  constitutional  formulae  with 
a  different  molecular  weight  from  that  implied  by  the  hexite-pentite 
theory.  Thus,  he  attributes  to  two  potash  micas  the  formulae  : 

KeH3Al12Si18Oeo  •  H6A16012  =  4.5  K20  •  4.5^H20  •  9  A1203  •  18  Si02, 
KflH6Al12Si18060  •  H6A16012  =  3  K20  •  6  H20  •  9  A1203  •  18  Si02, 


CONSTITUTION   OF  THE   SODALITES  61 

whilst  the  authors  of  the  hexite-pentite  theory  prefer  : 

3  K20  •  3  H20  •  6  A1203  •  12  Si02  =  K,H6(Si  •  Al  •  Al  -  Si),  and 
2  K20  •  4  H2O  •  6  A12O8  •  12  Si02  =  K4H8(Si  •  Al  •  Al  •  Si). 

This  contradiction  is  more  apparent  than  real,  and  the  fact  that 
J  of  the  aluminium  in  these  compounds  behaves  differently  from  the 
remainder  is  equally  well  shown  in  the  authors'  formulae.  Indeed, 
there  appears  to  be  no  important  reason  why  Thugutt  should  not 
substitute  the  formulae  : 

KeH2Al8Si12040  •  H4A1408,  and 
K4H4Al8Si12040 '  H4A1408, 

for  those  he  has  selected,  and  so  obtain  formulae  which  give  the  same 
molecular  weight  as  those  suggested  by  the  authors. 

Another  apparent  contradiction  to  the  authors'  theory  is  the 
nepheline  formula  calculated  by  Thugutt  from  a  series  of  analyses  in 
Hintze's  "  Handbuch."  In  this  calculation,  notwithstanding  that  he 
has  represented  nepheline  hydrate  and  potash  nepheline  by  formulae 
in  which  the  alumina-silica  ratio  is  1 :  2,  and  the  great  probability  that 
in  nepheline  itself  this  ratio  is  also  1  :  2,  Thugutt  selects  the  formula  : 

K2Na8Al10Sin042  =  K20  •  4  Na20  •  5  A1203  •  11  Si02 ; 

and  in  accordance  with  the  reaction  of  this  substance  with  alkaline 
carbonates  he  gives 

8  Na2Al2Si3010  •  4  Na2Al204  •  3  K2Al2Si3010, 

as  the  constitutional  formula. 

This  formula  is  quite  inexplicable  by  the  hexite-pentite  theory. 

As  a  matter  of  fact,  the  nepheline  analyses  by  Hintze135  do  not 
yield  a  formula  in  which  the  alumina-silica  ratio  is  1:2.  Several 
analyses  approach  very  closely  to  the  formula  : 

K20  •  4  Na20  -  5  A1203  •  12  Si02  =  K2Na8(Si  •  Al  •  Al  •  Si). 
Analyses 


Molecular 

Calculated 

Weights 

Composition 

XXIII 

XXV 

XXIV 

K2O    =     94 

5.98% 

5.66o/0 

4.76% 

5.05% 

4  Na20  =  248 

15.77% 

15.71% 

15.97% 

16.35% 

5A1203=  510 

32.45% 

32.66% 

32.06% 

33.28% 

12SiO2    =  720 

45.80% 

45.23% 

45.53% 

45.10% 

1572       100.00% 

It  is  conceivable  that  the  decomposition  products  of  nepheline 
must  be  the  same  as  those  of  nepheline  hydrate,  as  its  constitution  is 
analogous,  even  though  it  contains  a  different  alumina-silica  ratio. 

Thus,  the  consequences  of  the  hexite-pentite  theory  do  not,  as 
regards  minimum  molecular  weight,  contradict  the  facts. 


62  CONSEQUENCES   OF  THE   H.P.   THEORY 

VI 

The  conclusion  has  already  (see  pp.  22  to  26)  been  reached  that, 
of  all  the  theories  devised  for  showing  the  constitution  of  the  alumino- 
silicates,the  one  which  agrees  best  with  the  facts  is  that  which  assumes 
that  these  compounds  are  complex  acids  and  their  corresponding  salts. 

It  has  also  been  shown  that,  by  the  use  of  the  hexite  hypothesis 
respecting  the  arrangement  of  the  atoms,  most  of  the  objections  to  the 
"  complex  acid  theory  "  disappear.  Thugutt's  discovery  that  part  of 
the  aluminium  behaves  differently  from  the  remainder  and  that  of 
P.  Silber  that  in  nepheline  J  of  the  sodium  behaves  differently  from  the 
other  |  are  not  only  explicable,  but  are  direct  consequences  of  the 
theory.  A  complete  classification  of  a  large  number  of  alumino- 
silicates  is  also  rendered  possible  ;  the  felspars,  micas,  scapolites,  etc. 
need  no  longer  be  regarded  as  belonging  to  different  groups  of  minerals, 
but  may  be  considered  all  to  belong  to  a  single  class  of  compounds. 
They  can  only  be  conceived  as  salts  of  a  definite  series  of  alumino- 
silicic  acids,  and  the  "  mixture  theory  "  may  be  abandoned. 

Only  the  behaviour  of  andesite  now  remains  unexplained,  and  even 
this  will  become  clear  if  the  following  constitutional  formula — based 
on  the  hexite-pentite  theory — is  used  : 

Na  Na  Na 
I        I       ! 


i: 


Si  Al  j  Si 
\/\/\/ 

Ca  Ca  Ca 

I      I       I 

/\/\/\ 

I  Si  I  Al   Si) 


Na  Na  Na 


3  Na20  •  3  CaO  •  6  A1203  •  24  Si02. 

A  glance  at  this  structural  formula  of  andesite  shows  that  it  will 
react  with  NaCl  as  shown  by  the  following  equation  : 


Na  Na  Na 

Na  Na  Na  III 

I      I      I  /\/\/\ 

Al   Si 

Si  |  Al|  Si  |  VVV 

s/\/\/  I       I       I 

III  Na  ISa  Na 

Ca  Ca  Ca+6NaCl        =  +  3  CaCl2 

III  Na  Na  Na 

I       I 


ii 


I      I      I 

N* 


Na  Na  Na  I       I       I 

Na  Na  Na 


THE   POSSIBILITY   OF   ISOMERISM 


63 


The  complex  is  decomposed  and  the  re-formation  of  andesite  by 
means  of  CaCl2  (double  decomposition)  is  impossible. 

The  conception  of  the  aluminosilicates  as  complex  acids  thus  agrees 
excellently  with  experimental  results. 


VII 

From  the  structural  formulae  already  given  it  follows  that  two 
kinds  of  isomerism136  *  are  possible  : 

1.  An  isomerism  resulting  from  a  different,  yet  still  symmetrical, 
arrangement  of  the  basal  atoms,  or  "  Basis-isomerism,"  and 

2.  An  isomerism  due  to  the  ring  radicles,  or  "  Ring-isomerism." 
A  few  examples  will  make  this  clearer  : 


From  the  compound 


two  isomers  are  possible  : 


I.  Basis  isomerism 


/ 

K/Al/Si 
V 


From  the  compound 

H4Na6(Si  •  Al  •  Si), 
two  basis-isomers  are  also  possible  : 

Na  Na  Na  H    Na  H 

III  III 

H— /\/\/\— . H     Na—  /\/\/\— Na 

HI|s^M  H  Na_|siJ ^N_Na 

Na  Na  Na  H    Na  H 

I.  II. 


*  For  Literature  with  reference  to  Isomerism  in  inorganic  compounds  see  No.  136 
in  Bibliography. 


64  CONSEQUENCES  OF  THE  H.P.   THEORY 

II.  Ring  isomerism 

From  compounds  with  an  alumina-silica  ratio  of  1:2,  two  ring- 
isomers  are  possible  : 


5i|Al[Al|Si| 
/\/\/\/ 


Al  |  Si  I  Si   Al  | 

\/\/\A/ 

I.  II. 

From  the  derivatives  of  this  type,  analogous  ring-isomers  produce 
a  secondary  type  : 

|  Si  |  Al|  All  Si  I          <"Af|Si    Si|1fN 

\/ \/          X \/\/ ' 

I.  II. 

,/\ 

etc. 


iv. 


Crystallographic  and  chemical  investigations  have  already  indicated 
the  actual  existence  of  isomeric  aluminosilicates.    Thus,  potash  felspar 


\? 

is  already  known  in  two  forms,  viz.  as  orthoclase  (monoclinic)  and 
microcline  (triclinic). 

Soda  felspar,  /        Si 

K«  Al^Si 
V     \T 

is  also  known  to  occur  in  the  two  forms  of  sodium  orthoclase  (mono- 
clinic)  and  albite  (triclinic). 

The  following  results  of  work  by  Thugutt  confirm  the  existence  of 
ring-isomers :  In  the  previous  Section  it  was  shown  that  the  con- 
stitutional formula  of  the  sodalites  is  based  upon 

{Na12(Si  •  Al  •  Al  •  Si) }  2  •  m  2  •  n  H. 

Hence  the  existence  of  a  second  series  of  sodalites  with  the  formula 
{Na12(Al  •  Si  •  Si  •  Al)}2  •  m  2  •  nH, 

is  theoretically  possible.  As  a  matter  of  fact,  Thugutt  has  discovered 
two  chlorosodalites  with  a  different  behaviour  towards  calcium 
chloride,  although  the  chemical  composition  of  both  is  identical. 

The  artificially  prepared  hydrogen  sodalite  behaves  towards 
calcium  chloride  in  a  manner  quite  different  from  that  of  the  natural 
sodalites  from  Arendal,  Ditro,  Miask,  and  Turkestan. 


VARIOUS   KINDS   OF   COMBINED  WATER 


65 


The  artificial  variety,  on  treatment  with  calcium  chloride  solution, 
yields  a  calcium  chloride-sodalite  according  to  the  following  equation  : 

3  (6  Na20  •  6  A1203  •  12  SiO2  •  4  NaCl)  +  22  CaCl2 
=  3  (6  CaO  •  6  A1203  •  12  SiO2)  •  4  CaCl2  +  48  NaCl. 

With  natural  sodalites,  on  the  contrary,  the  equation  is  : 

2  (6  Na.O  •  6  A1203  •  12  Si02  •  4  NaCl)  +  12  CaCl2 
=  2  (6  CaO  •  6  A1203  •  12  Si02)  +  32  NaCl. 

It  is,  at  present,  impossible  to  say  which  formula  belongs  to  either 
of  the  two  isomers. 

^  Further  researches  will  show  how  far  these  prognoses  of  the  theory 
are  confirmed  in  this  respect  by  the  facts. 

VIII 

Water  may  be  present  either  as  "  water  of  crystallisation  "  or 
"  water  of  constitution, "  the  latter  being  acid-  or  base-water.  The 
"  acid-water  "  may  be  of  various  kinds  :  part  of  the  hydroxyl  groups 
may  be  united  to  the  aluminium  hexite  or  pentite,  the  remainder  to  the 
silicon  hexite  or  pentite. 

This  may  be  seen  from  the  following  formula,  in  which  the  different 
kinds  of  water  are  indicated  by  «,  ft,  y,  and  S,  respectively  : 


(ft) 

(«) 

(0) 

(OH)2 

OH 

(OH) 

i 

II 

1 

• 

(7) 

HO 

•Ca\ 

'V\/\/Ca- 

OH 

(r) 

(ft) 

HO/ 

Si 

Al 

Si 

\OH 

(0) 

(ft) 

H0\ 

\                . 

/OH 

(0) 

(7) 

HO 

•Ca/ 

\/ 

v 

\/ 

\Ca- 

OH 

(7) 

(OH), 

OH 

(OH) 

i 

08) 

w 

(ft 

6H20  (5). 


Since  Damour  first  drew  attention  to  the  change  in  the  behaviour 
of  the  water  in  hydrous  aluminosilicates  or  zeolites  at  higher  tempera- 
tures, this  subject  has  been  studied  by  various  investigators  (see  p.  4, 
last  line)  and  particularly  by  Clarke. 

Of  the  zeolites  examined  by  Clarke138,  those  relevant  to  the  present 
purpose  are  laumontite,  thomsonite,  hydronephelite,  heulandite, 
epistilbite,  stilbite,  faujasite,  scolecite,  foresite,  and  natrolite. 

The  Structural  Formulae  of  the  above-mentioned  Zeolites,  based  on 
their  behaviour  at  high  temperatures  (after  Clarke) 

I.   Laumonite 

Al4(Si04)5  •  Si308  •  Ca2H8  •  4  H20  =  4  H20  •  2  CaO  •  2  A1203  •  8  Si02  •  4  H20. 

II.   Thomsonite 

Al4(Si04)6Ca3(AlH202)2H4  •  3  H20 

=  4  H2O  •  3  CaO  •  3  A1203  •  6  SiO,  •  3  H20. 


66  CONSEQUENCES  OF  THE   H.P.  THEORY 

These  structural  formulae  were  suggested  by  Clarke  from  a  study  of 
the  dehydration  experiments  of  Damour,  Hersch,  and  others,  which 
showed  that  -f-  of  the  water  must  be  regarded  as  "  water  of  con- 
stitution." 

III.  Hydronephelite 

Al3(SiO4)3-Na2H-3H2O 
==  \  (2  Na20  •  H20  •  3  A1203  •  6  Si02  •  6  H20). 

IV.  Heulandite 

Al4(Si04)3(Si3O8)3Ca2H8  •  6  H20 
=  4  H2O  •  2  CaO  •  2  A1203  •  12  Si02  •  6  H20. 

V.  Epistilbite 

Al4(Si04)3(Si308)3Ca2H8  •  6  H2O 
=  4  H20  •  2  CaO  •  2  A1203  •  12  Si02  •  6  H2O. 

Epistilbite  is  stated  by  Clarke  to  have  the  same  composition  as 
heulandite,  but  the  water  in  it  appears  to  be  more  strongly  bound. 

VI.  Stilbite 

Of  the  same  composition  as  epistilbite  and  heulandite  ;  behaves  like 
heulandite  on  fusion,  but  sometimes  forms  anorthite. 

VII.  Faujasite 

Al4(Si04)4(Si308)2Na2CaH8  •  15  H2O 
=  4  H20  •  Na20  •  CaO  •  2  A1203  •  10  Si02  •  15  H20. 

VIII.  Scolecite 

Al4(Si04)6Ca2H8  •  2  H20  =  4  H20  •  2  CaO  •  2  A1203  •  6  Si02  •  2  H20. 

IX.  Foresite 

Al4(Si04)6CaH8  •  H20  =  4  H20  •  CaO  •  2  A1203  •  6  Si02  H20. 

X.  Natrolite 

Al2(Si04)3Na2H4  =  2  H20  •  Na20  •  A1203  •  3  Si02. 


The  Structural  Formulae  of  Laumontite,  Thomsonite,  etc.,  according  to  the 

Hexite-Pentite  Theory 

The  structural  formulae  suggested  by  Clarke,  when  rearranged  in 
accordance  with  the  hexite-pentite  theory,  yield  constitutional 
formulae  in  which  the  results  of  Clarke's  researches  may  also  be  seen, 
as  follows  : 

I.  Laumontite 

Clarke's  formula  multiplied  by  f  gives  : 


THE   CONSTITUTION   OF   THE   ZEOLITES 


67 


6  H30  •  3  CaO  •  3  A1203  •  12  Si02  •  6  H2O  =  H12Ca3(Si  •  Al  •  Si)  •  6  H20 


caOH  ca       caOH 


.(H0)  = 
«(HO)  = 


=  (OH), 
=  (OH), 


6H2O 


ca  =     Ca 


caOH  ca       caOH 
II.  Thomsonite 

Clarke's  formula  multiplied  by  2  gives  : 

8  H20  •  6  CaO  •  6  A1203  •  12  Si02  •  6  H2O  =  H16Ca6(SAi  •  Al  •  Al  •  Si)  •  6  H,0 
HOCa-OH  OHCa-OH 


,(HO)  = 


.(H0)  = 


A 
HO  Ca-OH 


=(OH)2 

Si    I  -6H20 

=(OH)2 

A 
OH  Ca-OH 


III.  Hydronephelite 
Clarke's  formula  multiplied  by  4  gives  : 
4  Na20  •  2  H20  •  6  A1203  •  12  Si02  •  12  H20  ==  H4Na8(ST  •  Al  •  Al  •  Si)  •  12H2O 


Na  H    H  Na 

I      I      I      I 
Na— /\/\/\/\— Na 


Na- 


Si 


Al 


Al 


Si 


12H20 


I      I      I       I 
Na  H    H  Na 


Ring-  and  Base-isomers  of  this  composition  are  clearly  possible. 

IV.  Heulandite 
Clarke's  formula  multiplied  by  f  gives  : 

/    /A 
6  H20  •  3  CaO  -  3  A1203  - 18  Si02  •  9  H20  =  H12Ca3l  Al^-Si  1  •  9  H2O 


ca   (OH) 


ca 


(OH)2= 


9H2O 


ca 


ca  --     Ca 


68 


CONSEQUENCES  OF  THE   H.P.  THEORY 


V.  Epistilbite 

Epistilbite,  according  to  Clarke,  has  the  same  composition  as 
heulandite,  but  the  water  is  more  strongly  bound. 

Possibly  epistilbite  has  the  following  structural  formula  : 


OH 


Oca 


HO      Si 
caO~\/ 


Al 


__/OH 
I  Oca 
OH 


9H20 


OH 


Oca 


ca  =  i  Ca 


as  in  this  the  water  would  be  bound  more  strongly  than  in  heulandite. 

VI.  Stilbite 
Clarke's  formula  multiplied  by  f  may  be  expressed  thus  : 

/    /Six 
6  H20  -  3  CaO  •  3  A1203  •  18  Si02  •  9  H20  =  H12Ca3l  Al~Si  1  •  9  H80. 

V     XSi 

Stilbite  is  either  analogous  to  heulandite  or  epistilbite  or  it  is 
an  isomeric  product  of  heulandite  with  the  following  formula  : 

(OH)2  ca 


ca- 


(OH) 


Si 


Al 


\' 
I 


(OH),.9 


&/\ 


ca  =  J  Ca 


(OH)2  |JX   'ca 
(OH)2ca 

VII.  Faujasite 

Clarke's  formula  multiplied  first  by  f  and  then  by  2  gives  : 
(6  H20  •  1.5  CaO  •  1.5  Na20  •  3  A1203  •  15  Si02  •  22.5  H20)2 


-2  •  45  H20 


THE   CONSTITUTION   OF  THE  ZEOLITES 


69 


(OH),  Oca 
//  ONa 


(W 


(OH). 

y 

^.  Oca 
(OH),  ONa 


45H2O 


VIII.  Scolecite 
Clarke's  formula  multiplied  by  3  gives  : 

12  H2O  •  6  CaO  •  6  A1203  •  18  Si02  •  6  H20 
=  H24Ca6(Si  •  Al  •  Si  •  Al  •  Si)  •  6  HaO 

OH 

(OH),  OH  Ca  OH  OH  (OH), 

II          I       \/       I         II 
HO-Ca,     A    /\    /\    X\    /\     ,Ca-OH 

HO— i 


ca  =  J  Ca 


Al    |   Si    |~°H       .6H20 


I       X\      I 

i,  OH 


(OH),  OH  Ca  OH  OH  (OH), 
OH 

Scolecite  is  of  special  interest,  inasmuch  as  it  must  contain  all  the 
four  different  kinds  of  theoretically  possible  water. 

IX.  Foresite 
If  Clarke's  formula  is  tripled  it  gives  : 

12  H20  •  3  CaO  •  6  A1208  •  18  Si02  -  3  H20 

=  H24Ca3(SAi  •  Al  •  Si  •  Al  •  Si)  •  3  H20 

OH 


Ca  •  OH  OHOHCa  OH  OH  OH  Ca  •  OH 

V    I    N/    J    \/ 

(OH),  = 


(OH),  = 


=  (OH), 
=  (OH), 


3H20 


(OH),  OH  (OH),  OH  (OH), 


70  CONSEQUENCES   OF  THE   H.P.   THEORY 

Foresite  contains  all  the  four  kinds  of  water  theoretically 
possible. 

X.  Natrolite 

Clarke's  formula,  if  multiplied  by  6,  leads  to  one  which  is  impossible 
according  to  the  hexite-pentite  theory,  as  compounds  with  an  alumina- 
silica  ratio  of  1  :  3  cannot  have  more  than  12  R2O.  This  does  not 
necessarily  prove  an  objection  to  the  theory,  as  Clarke,  in  publishing 
his  formula  for  natrolite,  definitely  pointed  out  that  the  character  of 
the  water  in  this  compound  is  doubtful. 

Further  investigations  will  show  that  this  compound  only  contains 
6  molecules  of  "  water  of  constitution." 

The  Hexite-Pentite  Theory  and  other  Zeolites 

Part  of  the  prognosis  of  the  theory  put  forward  by  the  authors  of 
this  volume  is  completely  confirmed  by  the  facts  ;  it  will,  therefore,  be 
of  special  interest  to  enquire  whether  other  investigations  of  zeolites — 
such  as  fractional  determination  of  water — will  lead  to  the  same 
conclusions  as  to  the  existence  of  water  in  four  different  forms  of 
combination  in  such  compounds  as  scolecite,  foresite,  etc. 

A  number  of  investigators,  following  the  researches  of  Friedel, 
E.  Mallard  and  E.  Rhine733,  have  concluded  that  the  zeolites  form  a 
remarkable  class  of  substances  which  differ  from  the  hydrates.  The 
work  of  A.  Damours,  who  showed  that  water  can  be  partially  absorbed 
by  dehydrated  zeolites  re-combined,  supports  this  conclusion.  There 
is  a  general  impression  that  the  loss  of  water  from  zeolites  does 
not  follow  the  laws  of  Dalton  and  Proust,  though  this  view  is  in  direct 
contradiction  to  the  experiments  of  Clarke.  This  view  has  been 
specially  supported  by  J.  M.  van  Bemmelen717,  E.  Doelter783,  F. 
Rinne718,  and  Sommerfeldt719,  but  A.  Johnson720  adopts  the  contrary 
view  and  maintains  that  the  evolution  of  water  is  not,  in  principle, 
different  from  that  of  normal  hydrates. 

J.  M.  van  Bemmelen  regarded  the  combination  of  water  in  zeolites 
as  similar  to  that  in  silica  jellies.  Doelter  regards  it  as  "  adsorbed." 
E.  Rinne  has  found,  in  the  case  of  heulandite  and  desmine,  that 
definite  changes  in  the  water-content  are  accompanied  by  equally 
definite  changes  in  the  optical  character  of  these  substances.  According 
to  him,  in  heulandite  and  desmine  an  equilibrium  is  formed  at  all 
temperatures  and  the  loss  of  water  is  dependent  on  external  circum- 
stances such  as  atmospheric  pressure  and  temperature. 

The  belief  that  loss  of  water  by  zeolites  does  not  follow  stoichio- 
metrical  laws  is,  without  doubt,  based  on  an  error.  Clarke,  for 
instance,  has  conclusively  shown  that,  in  the  case  of  heulandite,  the 
loss  of  water  is  quite  in  accordance  with  these  laws  and  that  in  the  case 
of  desmine  the  same  regularity  is  highly  probable.  The  apparent 
irregularities  are  due  to  the  use  of  too  small  molecular  weights  for  these 


THE   CONSTITUTION   OF  THE   ZEOLITES  71 

compounds,  whereby  the  regularity  of  the  loss  may  be  overlooked. 
That  this  is  the  case  with  heulandite  has  already  been  shown.    That  it 
applies  equally  to  desmine  is  not  difficult  to  prove,  as  follows  : 
Desmine  has  the  general  formula 

CaO  •  A1203  •  Si02  •  5  H20. 

According  to  the  H.P.  theory,  part  of  the  water  shown  is  "  water 
of  constitution"  and  the  remainder  is  "water  of  crystallisation" 
(p.  65),  the  structural  formula  being  : 


6  H20  •  6  CaO  •  6  A1203  •  6  Si02  •  4  (6  H20). 

It  is  clear  that  a  whole  series  of  water-separation  phases  may 
occur,  such  as  : 

1.  Conversion  of  two  hexites  into  pentites. 

2.  Conversion  of  the  remaining  hexite  into  pentite. 

3.  Separation  of  four  pentites. 

4.  Separation  of  four  hydroxyl  groups. 

There  are  at  least  ten  phases  of  water-separation  which  lead  to 
forms  differing  from  each  other  in  crystallographic  and  optical  charac- 
ters. In  short,  the  researches  of  Klnne,  rightly  considered,  really  agree 
with  the  consequences  of  the  H.P.  theory. 

The  compounds 

A.  (CaO  •  A1203  •  Si02  •  5  H20)6 

B.  (CaO  •  A1203  •  Si02  -  4  H20)6 

C.  (CaO-Al203-Si02-3H20)e 

D.  (CaO  •  A1203  •  Si02  •  2  H.O), 

E.  (CaO  •  A1203  •  Si02  •  H20)« 

F.  (CaO-Al203-Si02)6 

are  distinguished  by  their  different  optical  and  crystallographic 
properties  ;  the  compounds  A,  B,  and  C  being  monoclinic,  D  appears 
to  be  rhombic,  E  still  more  clearly  rhombic,  and  F  (which  has  no  water 
of  constitution)  is  amorphous. 

Sommerfeldt  considers  that  the  zeolites,  unlike  the  hydrates,  lose 
water  continuously,  and  regards  them  as  solid  solutions.  He  has 
applied  the  law  of  Ch.  Henry  and  the  second  law  of  thermodynamics 
to  zeolites  by  integration,  and  the  substitution  of  logarithms  for 
natural  numbers  in  the  formula  : 


(1)  U  = 


—  RT'd(ln^) 

C 


72  CONSEQUENCES   OF  THE   H.P.  THEORY 

in  which  the  concentration  of  the  water  in  the  solid  and  vaporous 
form  is  represented  by  c'  and  c.  He  devised  a  second  formula  in  which 
at  least  two  temperatures  are  known  and  are  proportionate  to  the 
maximal  tensions  of  the  water  vapour  and  that  of  the  water  occluded 
in  unit  volume  of  the  substance,  namely  c'2  :  c2.  The  heat  of  combina- 
tion may,  in  this  way,  be  calculated. 
From  the  formula  thus  obtained 

(2)  U=  +4-584  log.  (^!_jjt)-j!-T,    Calories, 

\  Cj_       C  a7    -L2 — -LI 

it  is  possible  to  ascertain  whether  the  usual  laws  of  thermodynamics 
are  applicable  to  zeolites.  If,  for  instance,  the  vapour  tension  of  the 
occluded  water  c'  and  the  heat  of  combination  U  in  the  formula  (2) 
are  sufficient,  the  zeolites  may  be  regarded  as  solid  solutions.  E. 
Sommerfeldt  has  determined  calorimetrically  the  evolution  of  heat,  £7, 
following  the  absorption  of  water  by  analcime,  and  obtained,  as  the 
result  of  three  tests,  the  values  1520,  1710,  and  1635  Cals.  for  the  heat 
of  combination  of  1  molecule  of  water,  i.e.  an  average  of  1622  Cals. 
From  the  percentage  of  water  by  weight  which  a  sample  of  analcime 
lost  on  being  heated  from  20°  to  T°C.,  whereby  it  is  in  equilibrium 
with  the  water  vapour,  the  maximum  temperature  of  which  can  be 
ascertained  from  G.  Friedel's  researches,  the  heat  of  combination  U 
may  be  found  to  be  approximately  8530  Cals.  This  disagreement 
shows  that  the  formula  (2)  cannot  be  applied  to  zeolites.  Hence, 
according  to  E.  Sommerfeldt,  zeolites  cannot  be  solid  solutions  ;  he 
regards  them  as  adsorption  products. 

This  conclusion  of  Sommerfeldt's  is  only  partially  correct,  as  the 
disagreement  of  the  value  found  with  that  calculated  merely  shows  that 
the  zeolites  are  not  solid  solutions.  It  does  not  show  that  the  water  is 
adsorbed,  i.e.  combined  in  non-stoichiometric  proportions.  Indeed, 
the  authors  of  the  present  volume  have  previously  shown  that  the 
available  experimental  material  only  indicates  that  the  zeolites  do  not 
differ  essentially  from  other  hydrates. 

The  objection  may  be  raised  that  the  chief  characteristic  of  zeolites 
— their  ability  to  re-combine  with  water  of  crystallisation,  as  shown  by 
Damour,  whereby  they  are  distinguished  from  other  compounds  con- 
taining water  of  crystallisation — is  inexplicable  in  terms  of  the  H.P. 
theory.  This  anomaly  is,  however,  merely  superficial.  The  power  of 
combining  with  water  has  been  exhaustively  shown,  elsewhere,  to  be 
due  to  : 

1.  The  number  of  hydroxyl  groups  belonging  to  the  water  of 
crystallisation,  and 

2.  The  nature  of  the  base  in  compounds  (salts). 

The  more  hydroxyl  groups  a  compound  contains,  the  closer  is  its 
relationship  to  ring- water.  In  saline  compounds  the  combining  power 
of  the  ring-water  is  also  dependent  on  the  nature  of  the  base.  Some 
complex  acids  have  a  close  relationship  to  ring-water  and  therefore 


PROGNOSES  73 

crystallise  with  a  relatively  large  number  of  water-rings.  The  sodium 
salts  of  these  acids  contain  less  water  of  crystallisation,  the  potassium 
salts  still  less ;  hence  the  water  of  crystallisation  in  the  sodium  com- 
pounds is  more  strongly  combined  than  in  the  analogous  potassium 
salts.  It  is,  in  fact,  probable  that  the  calcium  group  (O.Ca.OH)  near 
the  OH-groups  in  zeolites  causes  the  water-rings  which  have  been 
separated  to  re-combine.  This  property  of  re -combination — so  charac- 
teristic of  zeolites — cannot  properly  be  made  a  reason  for  separating 
these  compounds  from  others  containing  water  of  crystallisation, 
and  forming  a  separate  class  of  compounds  of  a  so-called  "  zeolitic 
character." 

IX 

The  hexite-pentite  theory  proposed  by  the  authors  enables  prog- 
noses of  the  chemical  composition  of  the  aluminosilicates  to  be  made. 
Two  kinds  of  prognoses  must  be  clearly  distinguished  : 

1.  Those  founded  on  the  proportion  of  base  in  the  compound 
(Base-prognoses)  and 

2.  Those  involving  the  presence  of  ring  radicles  (Ring-prognoses). 

1.  Base-prognoses 
From  a  study  of  formulae  of  the  type 

Si  •  Al  •  Al  •  Si  =  6  A1203  •  12  Si02, 
it  is  possible  to  predict  that 

1.  Compounds  having  such  a  formula  can  at  most  contain  10R20, 
and  that 

2.  From  formulae  of  this  type  the  composition  of  an  enormous 
variety  of  salts  can  be  predicted,  including  normal,  acid,  basic  or 
mixed  salts,  some  already  known  and  others  the  existence  of  which  has 
yet  to  be  proved.    By  replacing  the  hydroxyl  groups  by  halogens  a 
further  series  of  compounds  is  theoretically  possible. 

Thus,  the  existence   of  the  following  compounds  of  this  type  is 
readily  conceivable  ;  the  same  is  true  of  other  formulae  : 


,__Ma 

I-    ;;    |Si|Al|Al|Si|    ~  2.  —    |Si|Al|Al|Si 

~    \/\/  JNa~\/\/\/\/ 

Na  Na  Na  Na  K   K 

(Normal  Salt)  (Anhydric  Salt) 

Na  H   H    Na  Li  H    H    Li 

I      I      i       I  I       I       I       I 

4.  ^|Si|Al|Al|SiC^22 
Na  H    E[    lia  Li  Et    i    Li 

(Acid  Salt)  (Acid  Salt) 


CONSEQUENCES   OF  THE   H.P.    THEORY 


K2  Na  Na  K2 

II      I       I      II 


•rr-    

5.      *~|Si|Al|Al 
H2= 


:,  Na  Na  K2 

(Normal  Salt) 


6. 


Ca  K    K    Ca 

I       I       II 


Li2==YV 

Ca  K    K    Ca 

(Normal  Salt) 


7-  Si     Al    Al 

Mg=l     A    A 
\/\/\/ 


Mg 


Na2  H    H      Na2 

(Acid  Salt) 


Na  Na   Na    Na 
I        I        I        I 


=Mg       o  HO-Mg-f 


'HO-Mg- 


Si    Al 


Al 


Si 


v/ 

Na  Na  Na 

(Basic  Salt) 


,— Mg-OH 
)— Mg-OH 


Na 


9. 


2(HOMg)  = 

2(HOMg)  = 


Na2  H     H     Na2 
II        I        I        II 
/\/\/\/\ 


Si  I  Al  |  Al  I  Si 
\/\/\/\/ 
Na2  H:     li     Na8 

(Acid  and  Basic  Salt) 


=  (MgOH)2 
=  (MgOH)2 


Ba  H    H    Ba 


2(HOMg  •  • 

OMg)  =  /  \/  \/  \/  \= 

(Mg  •  OMgOH)2 

•    2(HOMg- 

OMg)  =  xxx/x/x/  = 

(Mg  •  OMgOH)2 

II      1      1      II 
Ca  H    H    Ca 

(Acid  and  Basic  Salt) 

(CaOH)2Na         Na 
II              1               1 

(CaOH)2 

II 

11. 


2(HO-Mg-0-Mg-0-Mg)  = 
2(HO-Mg-0-Mg-0-Mg)= 


(CaOH)2 


K 


=  (Mg-0-Mg.O-Mg-OH)2 
=  (Mg-0-Mg-0-Mg.OH)2 

(CaOH)2 


2.  Ring-prognoses 


From  each  primary  type  of  formula,  a  series  of  secondary  com- 
pounds may  be  devised.    Thus,  from  the  primary  type  : 

Si  •  Al  •  Al  •  Si 


PROGNOSES  75 

the  secondary  (a)     Si  •  A!  •  Al  •  Si,  and 

(6)     Si  •  Al  •  Al  •  Si,         may  be  produced  ; 

from  the  primary  :  Si  •  Al  •  Si  •  Al  •  Si 

the  secondary  :  (a)    Si  •  Al  •  Si  •  Al  •  Si, 

(6)     Si  •  Al  •  Si  •  Al  •  Si, 

(c)  SAi  •  Al  •  Si  •  Al  •  Si, 

(d)  Si  •  Al  •  Si  •  Al  •  Si, 

etc. 

It  has  already  been  shown  that  a  portion  of  the  aluminium  in 
epidote  is  replaceable  by  Fe=.  From  the  formula  for  tourmaline  (see 
Appendix)  it  may  be  concluded  that  part  of  the  aluminium  in 
aluminosilicates  is  replaceable  by  boron.  If  it  be  admitted  that  the 
aluminium  in  hexites  and  pentites  may  be  replaced,  in  whole  or  in  part, 
by  elements  capable  of  forming  sesquioxides — and  this  view  is  highly 
probable  and  is  supported  by  many  analyses — the  constitution  of  a 
large  number  of  compounds  may  be  represented. 

An  interesting  series  of  prognoses  may  be  based  on  the  properties  of 
the  mineral  "  ardennite,"151  in  which  part  of  the  aluminium  is 
replaced  by  vanadium.  The  composition  of  this  mineral  is  shown  by 
the  formula  : 

10  MnO  •  V205  •  5  A1203  •  10  Si02  •  5  H20, 

which  may  be  derived  from  : 

Si  •  R  •  R  •  Si 
the  structural  formula  being 


:\  Si  I  Al  I  Al  I  Si  ^=  •  5  HaO  =  10  RO  •  V205  •  5  A1203  •  10  Si02-5  H2O. 

•    \  A  /—< 


The  positions  indicated  by  dots  show  the  vanadium  atoms  in  the 
aluminium  hexite.  Vanadium  hydrate  is  Vd  Hi  (OH)5,  hence  the 
trivalency  of  the  dotted  positions. 

It  is  highly  probable  that  other  "  ardennites  "  will  be  found,  in- 
cluding the  following : 


1.     =<  Si|  Al     Al!  Si  >=-aq.  =  12R10-2V10.-4AlIOi-10SiOi-aq. 


76  CONSEQUENCES   OF  THE   H.P.  THEORY 


2.  I  Si  I  Al     Al  |  Si  |_  *  aq.  =  12  R20  •  V206  •  5  A1208  •  12  Si02  •  aq. 

~ \/\  /\  /\/~ 

II       I       I       II 

II       III      III       II 
=/\/'\/"\/\= 

3.  Si  Al  |A1  |  Si  I     =  -aq.  =14R20-2  V205-4Al203-12Si02-aq. 

=\A./\./\x= 

II      III       III       II  etc. 

The  replacement  of  the  silicon  by  allied  elements,  such  as  titanium, 
zirconium,  tin,  etc.,  is  also  possible,  and  a  further  large  variety  of 
compounds  becomes  conceivable.  For  instance,  in  the  formula 

(a)     Al  •  Si  •  Al, 
the  aluminium  atoms  may  be  replaced  by  those  of  boron  to  produce 

(6)     B  -  Si  •  B. 

If  the  silicon  in  (b)  is  replaced  by  Sn 

B  -  Sn  -  B, 

may  be  produced.  In  a  similar  manner,  by  replacing  aluminium  and 
silicon  in  substances  of  other  types,  a  large  number  of  borosilicates, 
aluminostannates  and  borostannates  become  theoretically  possible. 

Few  such  compounds  are  known  actually  to  exist ;  among  others 
is  nordenskioldite152 


f 

6  CaO  •  6  B203  •  6  SnOa  =  Ca6(B  •  Sn  •  B). 

Apart  from  those  aluminosilicates  whose  constitution  has  already 
been  described  under  the  term  "  a-complexes,"  there  is  a  smaller 
series — the  "  /^-complexes  " — which  must  be  represented  somewhat 
differently,  though  they  are  quite  analogous  to  those  previously 
mentioned.  These  include  sapphirin153 

5  MgO  •  2  Si02  •  6  A1203. 

The  constitution  of  this  compound  needs  some  explanation,  as  it 
has  already  (p.  35)  been  suggested  that  a  silicon  hexite  can,  at  most, 

unite  with  three  Al.    Hence  the  formula  : 


PROGNOSES  77 


R10(A1  •  Si2  •  Al)  ;    R2  =  Mg. 

Sapphirin  must,  in  fact,  be  regarded  as  a  salt  of  an  acid  derived 
from  the  hydrate  : 

Si   S=   (OH),, 

>0 

Si  =  (OH)  3 

and  from  two  hydro-aluminium-hexites  by  the  removal  of  the  elements 
of  water. 

Theoretically,  a  sapphirin  corresponding  to 

I      _  I 
Si  :  |  Al  y~ 

Si  :  |~AT  V 

I          ~l 

R8(Al.Si2-Ai);    R2  =  Mg, 

is  possible,  and,  as  a  matter  of  fact,  an  analysis  by  Damour154  and 
another  by  W.  Schluttig155  suggest  a  sapphirin  corresponding  to 

4  MgO  •  2  SiOa  •  5  A1203. 
If  the  aluminium  in  sapphirin  is  replaced  by 

Fe  =  ,  Cr  =  ,  Mn  E=  ,  B  =  ,  etc, 
and  the  silicon  by 

Ti,  Zr,  Sn,  etc., 

a  large  number  of  new  substances  will  be  formed. 
Howlite156  : 


Si  :  [B"  V 

I        I 

R8(B  •  Si2  •  B)  •  aq.  =  4  CaO  •  2  Si02  •  5  B203  •  aq., 

*  In  this  structural  formula,  the  oxygen  atoms  are  omitted  for  the  sake  of  greater 
clearness. 


78  CONSEQUENCES   OF   THE   H.P.   THEORY 

and  Avasite157 : 

I        __| 
Si  :  |  Fe  )>- 


Si: 


I  I 

H8(Fe  •  Si,  •  Fe)  •  5  H20  =  4  H20  •  2  Si02  •  5  Fe203  •  5  H20, 

are  of  this  nature. 

Theoretically,  another  class  of  ^-complexes  is  also  possible,  viz. 
those  producible  from  the  hydrate 

Al  =  (OH), 

>O 

Al  =  (OH), 

and  forming  silicon  hydrohexites  and  hydropentites  in  the  manner 
previously  described.  Compounds  of  the  following  types  may  thus  be 
obtained  : 

ii:ft"       ,   nA 

\    \/~~          Al:lJL/" 

\  I  \  -  II 

/  /\  / " 

Ai:|siL      ^:|_SL>= 

o  \/  II 

The  constitution  of  the  silicates 

2  CaO  -  KOH  •  A1203  •  12  Si02  (milarite)15', 

RO  •  A1203  - 10  Si02  -  5  H20  (ptioHte)159, 

RO  •  A1203  -  10  Si02  •  7  H20  (mordennite)160,  etc., 

thus  becomes  clearer. 


If  the  molybdenum  and  tungsten  complexes  are  truly  analogous  to 
the  aluminosilicates,  they  must  be  constituted  in  an  analogous  manner. 
Assuming  that,  on  the  one  hand,  molybdic  and  tungstic  acids  and, 
on  the  other  hand,  vanadic,  phosphoric,  arsenic,  and  antimonic  acids 
form  hexa-  and  penta-radicles  (hexites,  pentites,  hydrohexites  and 
hydropentites)  analogous  to  the  acids  of  silicon  and  aluminium, 
complexes  of  molybdenum  and  tungsten  together  with  their  compounds 
must  exist  or  be  capable|of  production,  which  may  be  termed  a-  and 


MOLYBDIC  AND  TUNGSTIC  COMPLEXES  79 

/5-complexes  ;  in  other  words  it  must  be  possible  to  conceive  a  large 
number  of  molybdic  and  tungstic  complexes  whose  constitution  may  be 
ascertained  from  the  hypothesis  just  mentioned.  It  is  clear  that  the 
chemical  properties  of  the  compounds  should  agree  with  the  structural 
formulae  assigned  to  them.  That  they  do  so  is  shown  below. 

It  is  now  necessary  to  consider  what  vanadium  molybdates  are 
theoretically  possible. 

a-Vanadomolybdic  anhydrides 


Mo-V- 
M5-V- 
V  •  Mo  • 

Mo 

V 

=  3 
=  3 

=  6 

V206- 
V205- 
V205- 

12 

10 

G 

MoO3, 
Mo03, 
Mo03, 

V  •  Mo  • 

V 

=  5 

V203- 

6 

Mo03, 

Mo  •  V  • 

V- 

Mo 

=  6 

V205- 

12 

Mo03, 

Mo-  V- 

V- 

Mo 

=  6 

V205- 

10MoO3, 

Mo-  V- 

V- 

Mo 

=  5 

V205- 

12 

MoO3, 

Mo-V- 

Mo 

•V 

•Mo 

=  6 

V205- 

18 

Mo03, 

Mo-  V- 

Mo 

•  V 

•Mo 

=  6 

V205  • 

16 

Mo03, 

Mo-V- 

Mo 

•V 

•Mo 

=  6 

V205- 

15 

Mo03, 

Mo-  V- 

Mo 

-V 

•M 

=  5 

V205- 

18 

Mo03, 

V-Mo- 

V- 

Mo 

•  V 

-9 

V205  • 

12 

Mo03, 

V-Mo- 

V- 

Mo 

•V 

=  8 

V205- 

12 

Mo03, 

V-Mo- 

V- 

Mo 

•V 

=  8 

V205  • 

10 

Mo03, 

/Mo 

V^-Mo 

=  3 

V205  • 

18 

Mo033 

XMo 

Mo^V 
XV 

=  9 

V205- 

6 

Mo08,  etc.  etc. 

From  the  existence  of  /?-aluminosilicates  it  may  be  concluded  that 
the  existence  of  analogous  /2-vanadomolybdates  is  also  theoretically 
possible.  These  are  formed  (1)  from  the  hydrate  : 

ViEE(OH)4 

>0 


and  molybdenum  hydrohexites  or  hydropentites,  and  (2)  from 


Mo  M  (OH), 
>0 

Mo  m  (OH)5, 


80 


CONSEQUENCES  OF  THE   H.P.   THEORY 


and  the  corresponding  ring-radicles  of  vanadic  acid.    In  the  first  case 
the  following  hydrates  are  produced  : 


I: 


w; 

A 

Mo 


V:    Mo 


H12(Mo  •  V2  •  Mb) 


(b) 


V  :    Mo  >- 
____  s 


H10(Mo  •  V,  •  Mo) 


(c) 

A 

1  M^  1       \7 

/\= 

iv/r/-\ 

II                           II 

Mo    :  V  : 

\y 

Mo 
\/  = 

'  Mo     :  V  :     Mo 

\                            f 

II                \          1! 
/         II 

' 

}\= 

=V  :     Mo 

=V  : 

0 

Mo 

1 

10  H20  •  V,05  •  18  Mo08  10  H20  •  V205  •  15  MoO, 


(e) 

1  1 


Mo    :  V  : 


Mo 


Mo    :  V  :    MO 


H16(Mo2>V2<Mo2) 
8  H20  •  V205  -  24  Mo03 


(f) 


i 


Mo 


:  V  : 


Mo     — 


H12(Mo2>V2<Mo2) 
6  H20  •  V205  •  20  MoOa 


MOLYBDIC  AND   TUNGSTIC   COMPLEXES  81 

When  the  hydrate  OV2(OH)8,  like  the  hydrohexites  and  hydro- 
pentites,  forms  condensation  products,  acids  of  the  following  anhy- 
drides : 

6  V205  •  16  Mo03, 
9  V205  •  22  Mo03, 
are  formed. 

Similarly,  a  series  of  /2-vanadomolybdates  may  be  formed  from 
OMo2(OH)10  and  vanadium  hydrohexites  or  hydropentites. 

If,  in  the  a-  and  /2-vanadomolybdates  mentioned,  the  vanadic  acids 
are  represented  by  phosphoric,  arsenious,  arsenic,  antimonious, 
antimonic,  and  other  acids,  and  the  molybdic  acids  by  tungstic  acid, 
the  existence  of  vanado-,  phospho-,  arseno-,  and  other  tungstates  and 
of  phospho-,  arseno-,  and  other  molybdates  becomes  theoretically 
possible. 

Proofs  of  the  Correctness  of  the  above  Formulae  for  the  Representation  of 
the  Chemical  Structure  of  Molybdic  and  Tungstic  Complexes 

It  has  been  repeatedly  stated  in  the  foregoing  pages  that  the 
changes  which  have  been  observed  to  occur  in  Nature  in  aluminosili- 
cates  make  it  highly  probable  that  under  suitable  conditions  they  may 
be  converted  into  one  another.  This  fact  not  only  agrees  with  the 
authors'  hexite-pentite  theory,  but  is  a  natural  deduction  from  the 
latter.  In  the  case  of  the  various  molybdic  and  tungstic  complexes, 
also,  there  is  the  possibility  that,  with  the  same  component  acids, 
they  will  be  mutually  convertible  in  the  widest  proportions,  if  their 
constitution  is  analogous  to  that  of  the  aluminosilicates.  For  instance, 
the  various  vanadomolybdates  are,  without  exception,  converted 
into  each  other  under  certain  conditions  :  the  vanadotungstates, 
arsenomolybdates  and  arsenotungstates  are  distinguished  by  this 
characteristic  property. 

The  best  experimental  confirmation  of  the  authors'  views  may  be 
found  in  the  researches  of  Friedheim  and  his  pupils,  whose  work  is 
characterised  by  the  great  exactitude  and  care  with  which  it  has  been 
carried  out. 

The  above-mentioned  property — convertibility — is  shown  in  the 
Tables  on  the  following  pages,  in  which  a  number  of  the  results  ob- 
tained by  Friedheim  and  his  pupils  have  been  summarised  : 

Table  A. — Action  of  a  small  quantity  of  Mo03  on  normal  vanadates. 

Table  B. — Action  of  Mo03  on  normal  vanadates. 

Table  C—  Action  of  chlorides  on  NH4  VO3+Mo03. 

Table  D. — Action  of  normal  vanadates  on  paramolybdates. 

Table  E. — Action  of  Mo03  on  normal  vanadates. 

Table  F. — Action  of  Mo03  on  phosphates. 

Table  G.— Action  of  Mo03  on  arsenates. 


CONSEQUENCES   OF   THE   H.P.   THEORY 


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CONSEQUENCES  OF  THE   H.P.  THEORY 


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CONSEQUENCES   OF   THE   H.P.   THEORY 


It  is  not  difficult  to  show  that  the  vanadomolybdates  given  in  the 
Tables  A,  B,  C,  D,  and  E  are  genetically  related  to  each  other,  as 
would  be  expected  from  the  theory. 

There  must,  of  necessity,  be  a  relation  between  vanadomolybdates 
in  Tables  A,  B,  and  C,  as  these  compounds  are  all  obtained  by  the  same 
method  from  different  proportions  of  normal  vanadates  and  Mo03. 
The  compounds  shown  in  Table  C  must  be  related  to  those  in  A  and 
B,  as  they  are  nothing  more  than  transformation  products  of  the 
latter.  Hence  the  following  genetic  relationship  between  the  vanado- 
molybdates : 

(a) 
(b) 
(c) 
(d) 

(e) 

(/) 
(9) 
(h) 

(i) 
(k) 

(D 


2R20 

•     V205 

•  6  MoOa, 

5R2O 

•  2  V205 

•  12  Mo03, 

7R2O 

•  3  V205 

•  18  Mo033 

R20 

•     V205 

•    3Mo03, 

2R20 

•     V205 

•    3Mo03 

3R20 

•  2  V205 

•    6Mo03 

2R20 

•  2  V205 

•    5Mo03 

3R2O 

•2V205 

•    4Mo03 

4R20 

•  3  Vo05 

•    5MoO3 

5R20 

•  4  V205 

•    6Mo03 

R20 

•     V205 

•       Mo03. 

Those  shown  in  Table  D,  viz.  : 

(a')  3  R20  •     V205  •    6  MoO3, 

(b')  5  R20  •  2  V2O5  •  12  Mo03, 

(c')  2R20-     V2O5-    4Mo03, 

(d')  2R20-     V205-    3Mo03, 

must  also  be  related,  as  they  have  been  produced  in  an  analogous 
fashion  from  normal  vanadates  and  paramolybdates. 

On  the  other  hand,  the  vanadomolybdates  (b')  and  (d')  have  a 
composition  analogous  to  (b)  and  (e)  in  Tables  A,  B,  and  C,  whereby 
the  relationship  of  the  various  molybdates  in  the  first  four  Tables 
enables  them  to  form  a  definite  class  of  compounds. 

Table  E  includes  the  following  : 


(&") 

(O 
(d") 
(O 


2R20 
5R20 
7R20 
2R20 
3R20 


V205 
2V205 
3V205 

V205 
2V205 


6MoO3 

12  Mo03 

18  Mo03 

4  MoO, 

4  MoO, 


From  this  Table  (E)  a  relationship  is  shown  between 

1.  a",  b",  c"  ; 

2.  a",  d"  and 

3.  V  e", 


so  that  a",  b",  c",  d"  >  and  e"  must  be  analogously  constituted. 


MOLYBDIC  AND   TUNGSTIC   COMPLEXES  89 

As  these  substances  are  also  shown  in  the  Summary  of  Tables  A, 
B,  C,  and  D 


a*  =  a, 


b"  =  b7  =  b, 

c77  =  c, 
d77  =  c7, 

e77  =  h, 

there  is  a  definite  actual  relationship  between  all  the  vanadomolyb- 
dates mentioned  in  Tables  A,  B,  C,  D,  and  E. 

It  is  obvious  that  there  can  only  be  one  theory  which  explains  all 
these  vanadomolybdates  satisfactorily.  The  authors'  hexite-pentite 
theory  does  this,  and,  what  is  more,  it  enables  the  existence  of  this 
relationship  to  be  predicted.  A  study  of  the  following  structural 
formulae  of  these  vanadomolybdates  leads  to  the  surprising  result  that 
a  large  number  of  the  theoretically  constructed  compounds  of  this 
group  are  actually  in  existence,  and  it  is  to  be  expected  that  the 
remaining  vanadomolybdates — which  are  theoretically  possible — 
will  be  discovered  sooner  or  later. 

The  vanadomolybdates  just  mentioned  clearly  possess  the  following 
structural  formulae  : 

.  /./*h 

(2  R20  -  V206  •  6  Mo03)3         =  R12  V^-Mo       (a,  a77), 


7  R20  •  3  V206  •  18  Mo03        =  R14(v^-Mo  I     (c,  c"), 

/      /MACK 

(5  R20  •  2  V205  -  12  MoO.K.5  =  B  J  V^-Mo  1     (b,  b7,  b77), 

V    Xl&/ 

(3R20-V205-6Mo03)3         =  R18(vr-Mo)     (a7), 

V    XT*/ 


(R20  •  V2O5  •  3  Mo03)6  =  R12(Mo  •  V  •  Mo  •  V  •  Mo)     (d), 

(2  R20  •  V205  •  3  Mo03)6  =  R24(Mo  •  V  •  Mo  •  V  •  Mo)     (d7,   ej, 

(3  R20  •  2  V205  •  6  Mo03)3  =  R18(Mo  •  V  •  Mo  -  V  •  Mo)     (f), 

(2  R20  •  2  V205  •  5  Mo03)3  =  R12(Mb  •  V  •  Mo  •  V  •  So)     (g), 

(3  R20  •  2  V205  •  4  Mo03)3  =  ~Rl6(Mo  •  V  •  V  •  Mo)     (e77,  h), 

(4  R20  •  3  V205  •  5  Mo03)2  =  R16(Mo  •  V  •  V  -Mo)     (i), 

(5  R20  •  4  V205  •  6  Mo03)2  =  R20(Y  •  Mo  •  V  •  Mo  -V)     (k), 

(R20  •  V205  •  Mo03)6  =  R12(V  •  MAo  •  V)     (1), 

(2  R20  •  V205  •  4  Mo03)3  =  R12(Mo  •  V  •  Mo)     (c7,  d77). 


90  CONSEQUENCES   OF  THE   H.P.  THEORY 

The  objection  may  be  raised  to  the  conception  of  the  a-vanadomo- 
lybdates  as  salts  of  complex  acids :  viz.  the  ratio  of  the  acid  components 
(V205  :  Mo03)  must  remain  unchanged  when  the  acids  are  treated 
with  salts  such  as  NaCl,  KC1,  etc.,  and  the  only  substitution  which  can 
take  place  is  by  means  of  monovalent  elements  such  as  Na,  K,  etc. 
With  the  vanadomolybdates,  however,  this  is  not  always  the  case. 
For  instance,  it  may  be  seen  from  Table  A,  that  the  compound 

(a')  5  (NH4)20  •  4  V205  -  6  Mo03  •  14  H20, 

on  treatment  with  KC1  is  converted  into 

(&')  3  K20  -  2  V2O5  •  4  Mo03  •  7  H20. 

The  acid  anhydride  ratio  in  (a')  is  2  :  3  and  in  (&')  it  is  1  :  2. 
From  the  same  Table  it  follows  that 

(c')  3  K20  •  (NH4)20  •  3  V205  •  5  Mo03  •  9  H20, 

on  treatment  with  KC1  is  converted  into 

(df)  3  K20  •  2  V205  •  4  Mo03  •  7  aq. 

In  (c')  the  ratio  of  V2O5  :  Mo03=3  :  5  and  in  (d')  I  :  2. 

In  this  connection  it  should  be  borne  in  mind  that — notwith- 
standing the  undoubted  existence  of  free  complex  acids  of  Mo  and  W, 
such  as  the  silicotungstate  SiO2  •  12  WO3,  silicomolybdate  Si02  • 
12Mo03,  phosphomolybdate  P2O5  •  24MoO3,  etc. — Friedheim  and 
his  associates  endeavoured  to  regard  molybdic  and  tungstic  complexes 
as  salts  of  related  acids  ;  they  conceived  the  idea  that  they  might  be 
double  salts  and  had  hopes  that  this  would  suffice  to  explain  the 
remarkable  conversions  they  had  observed.  And  yet  these  reactions 
are  by  no  means  so  puzzling  as  may,  at  first  sight,  appear.  Only  the 
a-complexes  of  the  aluminosilicates  can  be  distinguished  by  a  certain 
durability,  e.g. 

5.5  R20  •  6  A1203  •  16  Si02  (p.  39), 

in  Lemberg's  series.  Whatever  salts  are  allowed  to  act  on  the  com- 
pounds in  this  series  the  aluminasilica  ratio  remains  constant.  In  the 
a-components  of  the  molybdic  and  tungstic  complexes  this  is  not  always 
the  case  ;  they  are,  to  some  extent,  unstable.  The  aluminosilicates 
are  not  all  of  equal  stability.  Of  all  the  numerous  types  previously 
mentioned, 

SVA1-A1-SX 

the  kaolin  type,  is  the  most  stable.  It  is  well  known  that  the  action  of 
various  natural  (geological)  processes  is  to  convert  the  various  alumino- 
silicates into  compounds  of  the  kaolin  type. 

The  great  stability  of  compounds  of  the  kaolin  type  is  also  shown 
by  a  series  of  fusion  experiments  by  Doelter168,  who  found  that 


MOLYBDIC  AND  TUNGSTIC  COMPLEXES  91 

1.  Laumontite  : 

Ca3(Al  •  Si  •  Al)  •  12  H20, 

at  a  sufficiently  high  temperature,  loses  silica  and  water,  forming 
anorthite : 

Ca6(SAi  •  Al  •  Al  •  Si). 

2.  On  fusion,  natrolite  : 

Na12(Sl  -  Al  -  Si  •  Al  -  Si)  - 12  H20, 
produces 

Na12(Si  •  Al  •  Al  •  Si), 
silica  and  water. 

3.  On  fusion,  scolecite : 

H24Ca6(Si  •  Al  •  Si  •  Al  •  Si)  •  6  H20, 
yields 

Ca,(Si  •  Al  •  Al  •  Si), 
silica  and  water. 

If  the  vanadomolybdates  and  vanadotungstates  are  true  analogues 
of  the  aluminosilicates,  the  most  stable  of  the  a-compounds  must  be 

Mo  •  V  •  V  •  Mo,  and 
W-V-V-W. 
This  is  actually  the  case,  for  Friedheim  has  shown  that 

(a)     6  Na20  •  3  V205  •  6  W08, 
on  boiling  with  WO3,  is  converted  into 

(£)    6  Xa»0  •  3  V206  •  12  W08, 
and  on  fusing  ft  the  a-compound 

W  •  V  •  V  •  W, 
remains  behind. 

On  studying  the  puzzling  transformations  of  the  vanadomolyb- 
dates in  the  light  of  the  hexite-pentite  theory,  it  will  be  seen  that  the 
less  stable  a-compounds  are  converted  into  the  highly  stable 

Mo  •  V  •  V  •  Mo. 

The  conversion  of  (a')  into  (&')  and  (c')  into  (V)  may  be  represented 
as  follows  : 

V  •  Mo  •  tf  -  Mo  -  V  ->  Mo  •  V  -  V  •  Mo , 

(«')  (&') 

Mo  •  V  •  V  •  Mo        -- >  Mo  •  V  •  V  •  Mo . 

(O  (*') 


92    CONSTITUTION  OF  MOLYBD1C  &  TUNGSTIC  COMPLEXES 

No  double  decomposition  can  result  from  the  action  of  KC1  on 
(a')  or  (c'),  because  these  substances  are  unstable  in  solution,  as  may 
be  found  from  their  behaviour  when  attempts  are  made  to  crystallise 
them  from  such  solution.  The  ratio  V205  :  Mo03  in  compounds  of  the 

type  Mx>  .  V  .  V  .  Mo  is  not  affected  by  reactions  involving  double 
decomposition. 

The  most  stable  type  of  compound  may  be  represented  by 

Mo 


XMo 

deduced  from  the  conversion  of  (a")  and  (&")  into  (c")  (Table  E). 

No  less  interesting  is  Table  F,  all  the  compounds  of  which,  with 
the  exception  of 

6  K20  •  4  P205  •  9  Mo03  •  4  H20, 

may  be  accurately  represented  by  hexite-pentite  formulae,  thus  : 
(a)      (2  R20  •  P2O5  •  4  Mo03)3        =  Ri2(Mo  •  P  •  Mo), 
(6)      4  R20  •  3  P206  •  10  Mo03       =  R8(Mo~  •  P  •  Mo), 


(c) 

(R20-P205-2Mo03)6 

=  R12(Mo  •  P  •  P  •  Mo), 

(d) 

(4R2O-3P205-9Mo03)2 

=  R16(]\io  •  P  •  Mo  •  P  •  Mo), 

(e) 

7  R20  •  5  P205  •  16  Mo03 

=  R14(Mb  •  P  •  MAo  •  P  •  Mo), 

(/) 

(4R20-3P206-4Mo03)3 

=  R24(P  •  Mo  •  P  •  Mo  •  P), 

(9) 

(2R20-P205-5Mo03)3 

(/MCA 
P^-Mo 
XMo/ 

(gf)     (5  R20  •  2  P205  •  10  MoO,)l.B=  R15|  P^-Mo  | 

^Mo/ 


(f)     (3R20-P206-5MoO 


)         -  R   (V; 

3;3          —  rv18i  Jr\—. 
\     ^: 


(,ax 
P2^-M 
XMA 

(»)       2.5R2O-P205-24Mo03       = 

(t")      (3  R20  -  P205  •  24  Mo03)       = 

Altogether  this  series  affords  one  of  the  most  interesting  confirma- 
tions of  the  hexite-pentite  theory,  and  the  advantages  of  grouping 
together  these  substances  on  the  basis  of  their  analogous  mode  of 


GENETIC  RELATIONSHIPS   OF  ARSENOMOLYBDATES     93 

formation  are  readily  understood.  Friedheim,  on  the  contrary,  suggests 
the  following,  particularly  with  regard  to  the  compounds  (c),  (d),  (e), 
and  (/)  : 

"  Only  compound  (c)  of  the  previously  unknown  substance  —  the 
simplest  of  all  those  which  contain  phosphoric  and  molybdic  acids  —  is 
of  a  simple  nature  .  .  .  the  other  substances  are  undoubtedly  mix- 
tures." 

Friedheim  regards  the  compounds  (d),  (e),  and  (/)  as  "  mixtures  " 
simply  because  he  could  not  otherwise  explain  their  composition  !  The 
Table  is,  therefore,  only  of  value  in  so  far  as  it  shows  a  relationship 
between  the  a-  and  /3-phosphomolybdate  complexes  ! 

Table  G  leads  to  the  same  conclusions  as  the  others.  The  sub- 
stances in  it  may  clearly  be  expressed  in  the  light  of  the  hexite-pentite 
theory  as  follows  : 

(a)  (2  R20  •  As205  •  4  Mo03)3         =  Ri2(Mo  •  As  •  Mo), 
(a')     (3  R20  •  As205  •  4  Mo03)3         =  Ri8(Mo  •  As  -  Mo), 

(b)  (R2O  •  As206  •  2  Mo03)«  =  R12(MAQ  •  As  •  As  •  Mo), 


(c)      (R2O  •  As206  •  6  Mo03)8  =  R6 


(3R20-  As206-6Mo03)3 


(d)      (2R20-As205-5Mo03)3         =  R12(  As^-Mo 

|'Mo> 
As^-Mo 


/     / 

.5==Rl5|AsH 


(e)      5  R20  •  As206  •  16  Mo03 


(s\  1V1U 
A°s2^-jMo 
X/Mr. 


Of  further  interest  in  connection  with  the  hexite-pentite  theory 
are  the  series  of  salts170  produced  by  the  action  of  V205  on  potassium-, 
sodium-  and  ammomum-paratungstates  : 

1.  2  R20  •  V206  •  4  W03, 

2.  4  R2O  •  3  V205  •  12  W03. 

Of  these,  the  first  is  immediately  decomposed  by  acids — even  in  the 
cold — with  separation  of  almost  the  whole  of  the  tungstic  acid.  On 
evaporation  with  hydrochloric  acid,  the  tungstic  acid  is  precipitated 


94  CONSTITUTION   OF  SILICOTONGSTATES 

quantitatively  in  as  complete  a  manner  as  in  ordinary  tungstic  salts, 
though  in  this  instance  it  is  rendered  impure  by  the  co-precipitation  of 
vanadic  acid. 

Compounds  of  the  second  series  are  not  affected  by  acids. 

Friedheim  has  endeavoured  to  show  that  the  action  of  acids  on  the 
compounds  in  the  first  series  brings  about  a  separation  of  tungstic 
acid  because  they  have,  as  one  of  their  constituents,  a  paratungstate 
which  behaves  in  the  same  manner.  He  therefore  suggested  the 
following  equation  : 

(2  R2O  •  V205  •  4  W03)3  =  5  R20  •  12  W03  +  R20  •  3  V205. 

( Paratungstate ) 

The  compounds  of  the  second  series  he  expressed  as  shown  below, 
because  the  meta-tungstic  acids  behave  in  an  analogous  manner  : 

4  R20  •  3  V205  •  12  W03  =  3  (R20  •  4  W03)  +  &20  •  3  V205. 

( Me  t  atungs  tate ) 

Friedheim  himself  raised  the  following  objection  to  his  own  con- 
ception of  the  molecular  structure  of  the  compounds  of  the  first 
series171 : 

"The  aqueous  solution  of  the  compound  2  R20  •  V205  •  4  WO3 
yields  no  precipitate  on  the  addition  of  barium  chloride  or  silver 
nitrate,  but  on  evaporation  with  the  first  of  these  reagents  the  corre- 
sponding barium  salt  is  formed;  with  silver  nitrate  a  red  solution, 
which  changes  after  a  time  to  a  purple-reddish  crystalline  compound  of 
the  corresponding  silver  salt,  is  produced,  and,  if  the  solution  is  con- 
centrated, the  salt  crystallises  out  in  red  needles." 

It  is  scarcely  likely  that  the  compounds  2  R20  •  V2O5  •  4  W03 
contain  the  components  shown  by  such  a  formula,  as  the  latter  does 
not  indicate  a  substance  which  will  form  easily  soluble  barium  and 
silver  salts.  In  another  research,  Friedheim  regards  these  compounds 
atomically,  though  even  then  it  is  scarcely  possible  to  see,  from  Fried- 
heim's  structural  formula  (p.  21),  that  the  bonds  between  the  vanadium 
and  the  tungsten  are  different  in  the  second  group  from  what  they  are 
in  the  first.  Yet  this  difference  is  at  once  observable  in  the  following 
structural  formulae  based  on  the  authors'  hexite-pentite  theory  : 


W 


W 


-\/y\/ 


w 


v 


w 


I     II     I  I          I 

6  R2O  -  3  V206  •  12  W03        4  R20  •  3  V205  •  12  WO3. 

Valuable  confirmation  of  the  authors'  theory  is  also  found  in  the 
interesting  researches  by  Marignac172  on  the  silicotungstates.  His 
formula  (Si02  •  12  WO3)  at  once  suggests  hexite. 

For  the  compound 

4  H20  •  Si02  •  12  WO,, 


DIMORPHISM   OF  POTASSIUM   SILICOTUNGSTATE       95 

the  hexite-pentite  theory  shows  three  isomers  to  be  possible,  viz. : 


1. 


2. 


/\ 

w 


/\= 

W 


w 
\/ 


W 

\/ 


3. 

I  I 

,/\ 
W 


Marignac  prepared  two  isomeric  acids  and  two  isomeric  series  of 
salts  having  the  formula  4  R20  •  Si02  •  12  WO3. 

The  "  water  of  constitution  "  in  the  free  acids  and  in  some  of  the 
salts  may  be  demonstrated  in  a  very  accurate  manner,  as  the  acids 
4  H20  •  Si02  •  12  WO 3  •  29  H2O  lose  25  mol.  H2O  at  100%  another 
6  mol.  between  150°  and  220°,  and  are  completely  dehydrated  at  350°. 
Hence,  8  mol.  H2O  may  be  regarded  as  the  "  water  of  constitution  " 
as  shown  in  the  structural  formula  : 


W 

/ 


W 


\ 


The  calcium  salt,  2  CaO  •  2  H2O  •  Si02  •  12  W08  •  22  H20,  loses  16 
mol.  H20  at  100°,  and  it  also  contains  8  mol.  H20  as  "  water  of  con- 
stitution." This  may  be  expressed  thus  : 


(OH), 
KO-Ca     A 


HO 


W 


:Si 


(OH)2 

/\_Ca-OH 
W      OH 


(H0)2=x/  \/=(OH)2 

(OH)2        (OH)2 
The  potassium  salt 

2  K2O  •  2  H20  •  Si02  •  12  WOS  •  7  H,0 

occurs  in  thick  prisms  and  pearly  hexagonal  plates.    Its  dimorphism 
may  be  explained  by  the  use  of  the  following  formula  : 


l. 


TT  

H— 

K              .] 

A      / 

w|:Si:    V 
\/            \ 
i               1 

L 

\-H 
V 
/-H 

H 

I 


2. 


K— 
K— 


H 

/\_i 


W  :Si 


\/ 

i 


— K 


The  silicotungstates  may  also  be  regarded  as  representing  the 
/3-complexes  which,  in  molybdic  and  tungstic  compounds,  are  so  much 


96    ^-COMPLEXES  OF  MOLYBDENUM   AND  TUNGSTEN 

more  stable  than  the  a-complexes.  The  /3-complexes  usually  yield  free 
acids  and  the  salts  are  not  easily  converted  into  compounds  of  other 
series,  but  will  crystallise  from  their  aqueous  solution  without  any 
decomposition.  The  acid  component  ratio  also  remains  unaffected  by 
reactions  involving  a  double  decomposition. 

Theoretically,  the  following  compounds  may  exist : 


V 

4  R20  •  Si02  •  10  W03, 

and  Marignac  also  prepared  compounds  of  this  series. 

The  following  formulae  for  molybdic  and  tungstic  /5-complexes  are 
derived  from  compounds  mentioned  in  Dammer's  "  Handbook  "  : 

/3-complexes 

(a)  R2(Mo  •  A12  •  Mo), 

(6)  R4(W  •  B2  •  W), 

(c)  R8(Wj  Si  •  W), 

(d)  R8(Mo-Pt-Mo), 

(e)  R8(W  •  Pt  •  W). 

(a)    R2(Mo  •  A12  •  Mo). 
K20  •  A1203  •  10  Mo03  •  15  H20  (Parmentier173). 

(b)  R4(W-B2-W). 

2  BaO  •  B203  •  10  W03  •  16  H20  (Klein174). 

(c)  R8(W-Si-W). 

4  H2O  •  Si02  •  10  W03  •    3  H20  (Marignac175), 

3(NH4)20  -SiO2-10W03-    9  H20 

4(NH4)2O  -Si02-10W03-    8H2O, 

2  H20  •  2  K20  •  Si02  •  10  W03  •    8  H2O, 

4  K20  •  Si02  •  10  W03  •  17  H20, 

4Ag20  -Si02-10W03-    3H20, 

4  BaO  •  Si02  •  10  W03  •  22  H20. 

(d)    R8(Mo-P°t-Mo). 
4  Na20  •  Pt02  •  10  Mo03  •  29  H20  (Gibbs176). 

(e)     R8(W-P°t-W). 

4  (NH4)20  •  PtO2  •  10  W03  •  12  H2O  (Gibbs177), 
4  Na2O       •  Pt02  •  10  W03  •  25  H2O, 
4  K20        •  Pt02  •  10  W03  •  12  H20. 


/3-COMPLEXES  OF  MOLYBDENUM  AND  TUNGSTEN    97 

(a)  R,(Mo  •  A12  •  Mo), 

(b)  Re(Mo  •  Cr2  •  Mo), 

(c)  R8(W  •  B2  •  W), 

(d)  Rm(Mo  •  Si  •  Mo),  (m  =  4.8) 

(e)  R8(W  •  Si;  W), 
(/)  R2(Mo  •  Zr  •  Mo), 
(g)  R2(Mo  •  Ti  •  Mo), 

(h)  Rm(W-P2-W),  (m  =  2.4) 

(t)  Ri0(Mo  - 12  •  Mo). 

(a)  R6(Mo  •  Ai2  •  Mo). 

3  (NH4)20  •  A1203  •  12  Mo03  •  20  H20  (Parmentier178), 
3  K20         •  A1203  •  12  MoO,  •  20  H20, 
3  Na20       •  A1203  •  12  Mo03  •  22  H20. 

(b)  R6(Mo  •  Cr2  •  Mo). 

3  (NH4)20  •  Cr203  •  12  Mo03  •  20  H2O  (Struve179,  Parmentier180), 
3  K20         •  Cr203  •  12  Mo03  •  20  H2O  (S.), 

3  Na20       •  Cr203  •  12  Mo03  •  21  H20  (S.). 

(c)     R8(W-B2-W). 

2  K20  •  2  H20  •  B203  •  12  W03  •  16  H20  (Klein181), 

4  K20  •  B203  •  12  W03  •  21  H20, 
K20  •  3  BaO  •  B2O3  •  12  W03  •  28  H2O. 

(d)     Rm  (Mo  •  Si  •  Mo) ;  m  =  4.8. 

2  H20  •  Si02  •  12  Mo03  •     24  H20  (Parmentier182), 

2  H20  •  Si02  •  12  Mo03  •     30  H20  (Asch183), 
2(NH4)2O  •  Si02  •  12  MoO3  •      8  H20  (P.), 

2  K20  •  Si02  •  12  Mo03  •     14  H2O  (P.), 

2  K20  •  Si02  •  12  Mo03  •     16  H20  (P.), 

1.5  K20  •  0.5  H2O  •  SiO2  •  12  Mo03  •  1.35  H,O  (A.), 

2  Na2O  •  Si02  •  12  Mo03  •     21  H2O 

1.5  Na20  •  0.5  H20  •  Si02  •  12  Mo03  •  16.5  H20, 

2  Ag2O  •  Si02  •  12  Mo03  •     12  H2O, 

1.5  Ag2O  •  0.5  H20  •  Si02  •  12  Mo03  •  10.5  H2O, 

4  Ag2O  •  Si02  •  12  Mo03  •     15  H20, 

2  MgO  •  Si02  •  12  Mo03  •     30  H20, 

2  BaO  •  Si02  •  12  Mo03  •     24  H20, 

2  CaO  •  Si02  •  12  Mo03  •     24  H20. 

(e)     Re(W  •  Si  •  W). 

4  H20  •      Si02  •  12  W03  •  22  and  29  H20  (Marignac184). 
4  H20  •      Si02  •  12  WO3  •  20  H20, 

4  (NH4)20  Si02  •  12  W03  •  16  H2O, 
2  (NH4)20  .  2  H20  .      Si02 .  12  W03  •    6  H2O, 


98    ^-COMPLEXES  OF  MOLYBDENUM   AND  TUNGSTEN 


4 

K20- 

Si02- 

12  W03 

•20 

H20, 

2KaO 

•2 

H20- 

Si02- 

12W03 

•    7 

H20, 

2K2O 

•2 

H2O- 

Si02- 

12W03 

•16 

H20, 

3K2O 

•5 

H2O-2 

(Si02  - 

12W03) 

•25 

H20, 

4Na20 

•  '  • 

SiO2- 

12WO3 

•    7 

H20, 

2Na2O 

•2 

H20- 

Si02- 

12WO3 

•10 

H20, 

2Na2O 

•  2 

H20- 

Si02- 

12WO3 

•11 

H20, 

2Na20 

•2 

H2O- 

SiO2- 

12WO3 

•18 

H20, 

3  (2  Na2O 

•2 

H2O- 

Si02- 

12WO3 

•13 

H20) 

Na2O 

•3 

H2O- 

Si02- 

12  W03 

•14 

H20, 

Na20 

•3 

BaO- 

Si02- 

12WO3 

•28 

H20, 

2MgO 

•2 

H2O- 

Si02- 

12WO3 

•16 

HaO, 

5CaO 

•3 

H2O-2 

(SiO2  • 

12  W03) 

•47 

H20, 

2CaO 

•2 

H20- 

Si02- 

12WO3 

•20 

H20, 

2CaO 

•2 

H2O- 

Si02- 

12WO3 

•22 

H20, 

4  BaO 

• 

Si02- 

12  WO3 

•27 

H20, 

2BaO 

•2 

H2O- 

SiO2- 

12  W03 

•14 

H20, 

4  Na2N03, 


2  BaO  •  2  H20  •      Si02  •  12  W03  •  22  H20. 

(/)     R2(Mo  •  Zr  •  Mo). 

2  (NH4)2O  •  ZrO2  •  12  Mo03  •  10  H20  (Pechard185), 
2  K20  •  Zr02  •  12  Mo03  •  18  H20. 

(g)    K2(Mo  •  Ti  •  Mo). 

2  K20  •  Ti02  •  12  MoO3  •  20  H2O  (Pechard186), 
2(NH4)2O-Ti02-12M03    •  10  H20, 
2  K20  •  Ti02  •  12  M03    •  16  H20. 


(h)    Rm(W-P°2 

•W);                    m 

P20 

5 

•12 

W03- 

42 

H 

20  (Pechard187), 

2  (NH4)20 

•  P20 

5 

•12 

WO3- 

5 

H 

.0, 

K2O 

•P2O 

5 

•12 

W03- 

9 

H 

.0, 

2  Na2O 

•P20 

5 

•12 

WO3- 

18 

H 

2o, 

Li2O 

•P20 

5 

•12 

W03- 

12 

H 

,0, 

T120 

•P20 

5 

•12 

WO3- 

4 

H 

,0, 

Ag20 

•P20 

5 

•12 

W03- 

8 

H20, 

2CuO 

•P20 

5 

•  12  WO,  • 

11 

H 

A 

2ZnO 

•P20 

5 

•12 

W03- 

7 

H 

.0, 

2PbO 

•P205 

•12 

W03- 

6 

H 

.0, 

2MgO 

•P20 

5 

•12 

WO3- 

10 

H 

2o, 

2CaO 

•P20 

5 

•12 

W03- 

19 

H 

A 

2SrO 

•P205 

•12 

W03- 

17 

H 

2o, 

2  BaO 

•P20 

5 

•12 

W03- 

15 

H 

20. 

2.4. 


(t)    R10(Mo  •  I2  •  Mo). 

5  (NH4)20  •  I2O7  •  12  Mo03  •  12  H2O  (Blomstrand188), 
9  K20  •  H2O  •  2  (1,07  •  12  MoO3)  •  24  H20, 
5  NaoO  •  I207  •  12  Mo03  •  26  HoO, 
5  Na20  •  I207  •  12  Mo03  •  34  H20, 


^-COMPLEXES  OF  MOLYBDENUM  AND  TUNGSTEN     99 


5  Li20  • 
5  Li20  • 

5  CaO  • 
4  CaO  • 
4  SrO  •  Na2O 


I207  • 
I2O7  • 
I207  • 
I207  • 
I2O7 


9  BaO  •  Na«0  •  2  (I207  • 
2  MnO  •  3  Na20  •  I207 

R2 


12  Mo03 
12  Mo03 
12  Mo03 
12  Mo03  • 
12  MoO3 
12  MoO3) 


15  H20, 
18  H2O, 
26  H20, 
21  H20, 

•  20  H20, 

•  28  H20, 


12  Mo03  •  32  H20. 


(/Mo 
P/M-o 
^Mo 


K20  •  P205  •  15  Mo03  (Rammelsberg189). 


(a)    R3 


(&) 


(c)     R, 


(  °    /M°\ 
\^$} 

*'K| 

B.f  (•/*); 
V     \w/ 


m  =  1.2. 


V  ^MW 


(a) 


5  (NH4)2O  •  Mn203  •  16  Mo03  •  12  H20  (Struve190), 
5  K20  •  Mn203  •  16  MoO3  •  12  H20. 


3(NH4)20 


Mo 


3  (NH4)20 

2  BaO  •  (NH4),0 

6  (NH4)20 

3K20 

2  H20  •  4  K2O 

5  H20  •  CaO 

3  BaO 


(a)    R6 


•  P206  •  16  MoO3  •  14  H20  (Kehrmann191 

(c)    Rn/P2^w];             m  =  6.i: 

P2O5  •  16  W03  • 

69  H20  (Kehrmann192), 

P205  •  16  W03  • 

16'H,0 

P205  •  16  W03  • 

xH20, 

P203  •  16  W03  • 

2H20, 

P205  •  16  W03  • 

16  H2O, 

P205  •  16  WO,  • 

19  H20, 

P205  •  16  WO3  • 

3H20, 

P205  •  16  WO,  • 

xH20. 

/        ^°\ 

*<i 

100    ^-COMPLEXES  OF  MOLYBDENUM  AND  TUNGSTEN 

/        W^ 

/  -          > 

(b) 
(c) 

(J.TJAJ> 
P2/Mo 

(3  —  x)  Na,0  •  P205  •  18  Mo03    (25  +  x)  H20    (Finkener193). 


*••(*<!) 


•  6  K20  •  P205  •  18  WO3  •  23  H20  (Gibbs194), 

6  K20  •  P.,05  •  18  W03  •  30  H20, 
K20  •  5  H20  •  P205  •  18  W03  •  14  H20. 

MCK 


, 

(c)     R12lAs/MoJ 


As205  •  18  Mo03  •  30  and  28  H20  (Pufahl196), 
2  (NH4)20  •  4  H20  •    As205  •  18  MoO3  •  13  H20  (Mach196), 
3K2O-3H20    -    As205-18Mo03-25H2O, 
K20  •  5  H2O    •    As205  •  18  Mo03  •  21  H2O, 
3K2O-3H2O    -    As205  •  18  MoO3  -  21  H2O, 
3  Li20  •  3  H2O    •    As2O5  •  18  Mo03  •  31  H2O, 
6T12O  •    As205-18Mo03-  x  H20, 

3T12O-3H20    •    As205  •  18  MoO3  •    3  H20, 
6Ag2O  •    As2O5  •  18  Mo03  •  22  H20, 

7  Ag20  -  5  H2O  •  2  (As205  •  18  MoO3)  •  22  H20, 
3CaO-3H20    -    As,O.  •  18Mo03  •  29  H20, 
3SrO-3H2O    .    As2O5  •  18  MoO,  •  29  H20, 

3  MO  •  3  H20    •    As2O5  •  18  MoO,  •  33  H2O  (M  =  Mg,  Cd,  Mn,  Co), 
3  MO  •  3  H20    -    As205  •  18  MoO.  •  34  H20  (M  =  Zn,  Cu,  Ni), 


I     .Vo. 

t»  •     «  r 


^-COMPLEXES  OF  MOLYBDENUM  AND  TUNGSTEN     101 


3  H2O  •  P205  •  20  Mo03  -21,  38  &  48  H20  (Debray197), 

2  Ag2O  •  P2O5  •  20  Mo03  •    7  H20, 

3  K2O  •  P2O5  •  20  MoO3  •    3  H20, 
7  Ag20  •  P8O5  •  20  Mo03  •  24  H20. 

W\.  /W 


P205  •  20  WO3  •  62  H20  (Pechard198), 
P205  •  20  W03  •  50  H2O  (P.), 
6  BaO  •  P205  •  20  W03  •  48  H2O  (Gibbs199). 

o  /Mo\  o  /Mo 


As205  •  20  Mo03  •  27  H20  (Debray200), 
3  K20  •  As205  •  20  Mo03  • 

/Mo\o  /Mcr 


o    /oo          o\ 

MMO>>\MO) 


Mo\0  /Mb-, 

m  =  6,  14. 


3(NH4)2O  •      P205-22Mo03  •    9  H2O  (Gibbs201), 

3  (NH4)2O  •      P205  •  22  Mo03  •  12  H20  (Rammelsberg202), 

3K2O  •      P205-22Mo03  •  (R.), 

5  K2O  •  H20   •  2  (P2O5  •  22  MoO3)  •  21  H20  (R.), 

7  Ag20  •      P205  •  22  Mo03  •  14  H20  (G.). 


^,  6,8,14. 


P205  •  22  WO3  •       7  H20  (Kehrmann203)  and 
2  K20  •  P2O5  •  22  W03  •       6  H2O  (Gibbs204),  (Freinkel), 

3  (NH4)2O  •  P2O5  •  22  W03  -  21  H2O  (G.), 

4  BaO  •  P205  •  22  W03  •  41  H20  (G.), 

7  K20  •  P205  •  22  WO3  •  x  H20  (K.  and  Fr.), 

7  BaO  •  P205  •  22  W03  •  59.5  H2O  (Sprenger,  K.  and  Fr.), 
3  BaO  •  4  Ag20  •  P205  •  22  W03  •      x  H20  (K.205). 


« *"(!><!) 


102 


THE   CONSTITUTION  OF  CLAYS 


3  (NH4)20 

(9-x)(NH4)20 

5  (NH4)20 

2K20 

(3— x)Na20 


3  H20  •  P205  •  24  Mo03  •  27,  46  &  59  H20 

(Gibbs206),  Finkener207),  Kehrmann203), 
P205-24Mo03  •  (Hundeshagen209), 

(P2O5  •  24  Mo03)  (Gibbs), 

P205-24Mo03  -16H20, 
P205-24Mo03  -  3H20, 
P205  •  24  Mo03  -  (58  +  x)  H20. 


m  =  2,  4,  6. 


xH20 
H20 
H»0 


P206  •  24  WO 


3  (NH4)20 

3K20 

3Na2O 


PA 
PA 
PA 


40,  59  and  60  H2O 

(Pechard210),  (Gibbs211),  (Sprenger212), 
24  W03  •         20  H2O  (Gibbs), 
24W03-         11  or  17H20  (Gibbs), 
24  W03  •         22  H2O 

(Brandhorst  and  Kraut213),  (Kehrmann214), 


2BaO 

•PA 

•24 

W03- 

46  H20, 

2Na20 

•PA 

•24 

W03- 

27  H20, 

3Ag20 

•P205 

•24 

WO3- 

58  H20, 

Ag20 

•P205 

•24 

W03- 

60  H2O, 

3CaO 

•PA 

•24 

WO3- 

58  H20, 

3BaO 

•P205 

•24 

W03- 

58,46  H20, 

2BaO 

•PA 

•24 

WO3- 

59  H20, 

BaO 

•PA 

•24 

W03- 

60  H20, 

etc.  etc. 


XI 


The  Constitution  of  Clays 

The  hexite-pentite  theory  shows  the  possible  existence  of  a  large 
number  of  aluminosilicic  acids  in  the  form  of  hydrates  and  anhydrides. 
Thus,  if 

Si  •  Al  •  Al  •  Si, 
is  taken  as  the  type,  the  following  hydrates  are  possible  : 


, '  Y  Y  Y 

H;2(Si  •  Al  •  Al  •  SAi) 

4. 


_x\/\ 


Si 

\/ 


Al 


HJ2(Si  •  Al 


/\= 

Si 
\X  = 

Al  •  SAi) 


A 


I      II 
\/\ 

Si 


Al-Si) 


Si    A1|A1 

'Y 

HJ2(Si  •  Al  •  Al  • 

6. 


THE   CONSTITUTION   OF  CLAYS 


103 


1    1 

AA/s/V- 

/\/\/\/\ 

Si 

AlJAljSi 

Si  Al  Al   Si 

\/ 

(Si 

YYx/~ 

•  Al  -  Al  •  S'i) 
7. 

1      1      1      1 
H°(Si  •  Al  •  Al  •  £ 
8. 

A. 

Si   Al  Aljsi 
\/\/\/\/ 

H°(Si  •  Al  -  Al  •  SAi) 
9 


X\/\X\/\ 


Si    Al  Al    Si 


HJ  (SAi  •  Al  •  Al  •  SAi)  H°(Si  -  Al  •  Al  •  Si) 

10.  11. 

Of  the  above  hydrates  or  aluminosilicic  acids,  Nos.  3,  4,  and  6, 
also  2  and  5,  also  9,  10,  and  11  are  isomeric.  If  all  the  contained  water 
is  completely  separated,  the  anhydride 

Si  •  Al  •  Al  •  SAi 
is  formed. 

The  above  hydro-alumino-silicates  may  also  contain  a  variable 
proportion  of  "  water  of  crystallisation,"  the  number  of  hydrates  being 
thereby  increased. 

Analogous  hydrates — with  or  without  water  of  crystallisation — 
may,  naturally,  be  regarded  as  of  other  types  ;  by  the  complete  loss  of 
their  contained  water,  these  hydrates  may  form  a  corresponding  series 
of  anhydrides.  The  following  hydrates  and  the  corresponding  anhy- 
drides thus  become  theoretically  possible  : 


Si   Al    Si      aq. 


rr 

i. 


2. 


/ 


I      X 


! /\ I 

Si  [Al   Si  V- 

r~\/ 


y    i 


-<u« 


<$ 


Al 


<$ 


5. 


6. 


7. 


104  THE   CONSTITUTION   OF  CLAYS 


_ 

<(Si  Al  Si  >        etc.  etc. 


These  substances  have  seldom,  if  ever,  been  prepared  synthetically, 
though  their  occurrence  in  Nature  is  well  known  under  such  widely 
different  names  as  "  Minerals  of  the  Allophane  Group,"  "  Clays,"  and 
"  Kaolins."  They  have  been  formed  out  of  the  most  diverse  materials, 
such  as  micas,  felspars,  chlorites,  etc.,  by  removal  of  the  base,  hydra- 
tion  and  subsequent  removal  of  the  water  under  definite  conditions.* 
These  acids  are  seldom  found  in  a  chemically  pure  state,  but  usually 
contain  small  proportions  of  the  original  base.  Hence  some  of  them 
may,  rightly,  be  termed  strongly  acid  salts. 

Their  formulae  have  seldom  been  calculated  from  analyses,  as  these 
materials  have  usually  been  regarded  as  4 '  mixtures . ' '  The  formulae  cal- 
culations of  some  minerals  of  the  allophane  group215  (see  Appendix) 
showed  that  these  substances  are  hydro-aluminosilicates  (with  a  small 
lime  content)  of  the  type 

Al  •  Si  •  Al  and  Al  •  Si  •  Al. 
From  the  analyses,  the  following  formulae  were  calculated  : 

1.  0.5    CaO  •  6  A1203  •  6  Si02  •  32  H20, 

2  0.5    CaO  •  6  A1203  •  6  Si02  •  38  H20, 

3.  0.75  CaO  •  6  A1203  •  6  Si02  •  32  H20, 

4.  0.25  CaO  •  6  A1203  •  5  Si02  •  32  H20, 

5.  0.75  CaO  •  6  A1203  •  6  SiO2  •  42  H20. 

Part  of  the  water  present  is  in  the  form  of  "  water  of  crystallisa- 
tion "  and  part  as  "  water  of  constitution."  It  is  not  possible  to  state 
a  priori  how  much  water  exists  in  either  or  both  these  forms,  but  the 
maximum  proportion  of  "  water  of  constitution  "  which  is  possible 
may  be  predicted  on  theoretical  grounds,  as  in  the  two  following 
structural  formulae  : 

I      ii      I 
_/\/\/\_ 

Al  I  Si   Al  I  I  Al  I  Si 


I       ii      I 

Maximum  of  H2O-Mols.  Maximum  of  H2O-Mols. 

(6)  (5) 

*  The  various  theories  as  to  the  origins  of  clays  are  described  in  the  translator's 
"British  Clays"  70<J  and  "Natural  History  of  Clay  "732.— A.  B.  S. 


THE   CONSTITUTION   OF   CLAYS  105 

The  determination  of  water  present  after  heating  these  substances 
to  a  high  temperature  should,  therefore,  be  of  value. 

Equally  interesting  is  the  calculation  of  the  formulae  of  a  number 
of  washed  clays  from  the  analyses  published  in  C.  Bischof's  "  Collected 
Analyses  of  Materials  used  in  Clay  working,"  published  in  1901  (see 
Appendix — 'Clays/  Section  B). 

These  analyses  agree  with  the  theory  that  a  number  of  hydro- 
aluminosilicates  may  exist  in  which  the  alumina-silica  ratio  varies 
within  extremely  wide  limits,  so  that  the  hydro-aluminosilicates 
themselves  may  be  of  the  most  widely  varying  nature.  The  analyses 
indicate  the  following  substances  : 

(a)      Si  •  R  •  Si, 
(6)      Si  •  R  •  Si, 

(c) 


A/Si 

Si 

(e)      Si  •  R  •  R  •  Si, 
(/)       Si  •  R  •  R  •  Si, 
(g)      Si  •  R  •  S'i  •  R  •  Si, 
(h)      Si  •  R  •  Si  •  R  •  Sf, 
(»)       S'i-R-Si-  R  -Si. 

More  accurate  calculations  of  the  formulae  from  analyses  by  the 
same  investigator  (see  Appendix — '  Clays/  Section  C)  gave  the  follow- 
ing : 

I.     0.5  CaO  •  5.5  H2O  •  3  R203  •  15  Si02  =  H^Ca^ 

II.    0.25  K2O  •  19.75  H20  (5  R2O3  •  12  Si02)2  =  [H$0(Si  •  R  •  R  •  Si)]2 

(-(-some  K.), 

III.  0.5  R2O  •  15.5  H2O  6  R2O3  •  16  Si02  =  H21Rg.5(Si  •  R  •  Si  •  R  •  Si) 

•  5  H20, 

IV.  0.5  CaO  •  15.5  H20  •  6  R203  •  16  SiO2  =  H°2lCa°.5(Si  •  R  •  Si  •  R  •  Si) 

•  5  H20, 

VIII.    0.5  K20  •  8.5  H20  •  5  A1203  •  16  Si02  =  H;7K°(Si  •  Al  -Si  •  Al_-_Si), 
IX.     0.5  K2O  •  9.5  H2O  •  6  R203  •  15  Si02  =  H?9K°(Si  •  R  •  Si  •  R  •  Si),_ 

XII.    0.25  K20  •  9.75  H20  •  6  R203  •  16  Si02  =  H°20(Si  •  R  •  Si  •  R  •  Si) 

(-f- some  K.), 

XIII.     12  H20  •  6  R203  •  18  Si02  =  H°4(Si  •  R  -Si  •  R  •  Si), 
XV.     10  H20  •  5  R203  •  12  Si02  =  H$8(Si-  R  •  R  •  Si)  •  H2O. 


106  THE   CONSTITUTION   OF  CLAYS 

These  compounds  contain  only  very  small  proportions  of  base  and 
may,  therefore,  be  regarded  as  hydro-aluminosilicates.  The  constitu- 
tional formulae  *  suggested  are  only  tentative  so  far  as  their  "  water 
of  constitution  "  is  concerned  ;  it  is  not  impossible  that  in  some  of 
them  a  part  of  what  is,  above,  included  under  the  term  "  water  of 
constitution  "  may,  in  reality,  be  in  the  form  of  "  water  of  crystallisa- 
tion." The  only  means  of  ascertaining  this  is  to  make  determinations 
of  the  water  left  after  heating  the  substances  to  various  high  tempera- 
tures. 

Further  formulae  calculated  from  the  analyses  of  the  foregoing  and 
other  clays  will  show  whether  the  other  theoretically  possible  hydro- 
aluminosilicates  are  known  to  occur  in  Nature  or  to  have  been  prepared 
artificially. 

According  to  the  authors'  hexite-pentite  theory,  clays  must  have 
the  properties  of  acids.  The  following  equation  represents  the  action 
of  sodium  carbonate  : 

Si  •  Al  •  Al  •  Si  -f  6Na2C03  =  Na°12(Si  •  Al  •  Al  •  Si)  +  6C02. 

According  to  Vernadsky216  haloid  salts  (KI,  KBr,  etc.)  decompose 
clays  at  moderate  and  high  temperatures,  with  separation  of  haloid 
salts. 

The  acidity  of  clays  is  also  shown  by  their  mode  of  formation  in 
Nature.  They  are  formed  by  the  decomposition  of  aluminosilicates 
under  the  same  conditions  as  hydrates  and  anhydrides  are  formed  by 
the  decomposition  of  their  salts.  Thus,  in  Nature,  the  decomposition 
of  simple  silicates  by  the  action  of  water  and  carbonic  acid  produces 
opals,  and  a  similar  decomposition  of  aluminosilicates  produces 
clays. 

The  necessary  consequence  of  the  hexite-pentite  theory — that  clays 
are  single  chemical  compounds  and  not  mixtures — is  by  no  means  new. 
So  far  as  certain  Alsatian  fireclays  are  concerned,  this  conclusion 
was  reached  by  C.  Mene  in  a  prize  essay  published  in  1863,  in  which  he 
made  the  following  noteworthy  statement : 

"  The  clays  used  for  the  manufacture  of  firebricks  are  compounds 
of  definite  chemical  composition  and  are  decomposition  products  of 
rocks  of  equally  definite  chemical  composition." 

This  work  of  Mene's  appears  to  have  been  overlooked,  and  many 
modern  scientists  generally — though  erroneously — regard  clays  as 
mixtures  of  quartz,  felspar  and  the  so-called  "  clay  substance."  This 
highly  mistaken  view  of  the  chemical  nature  of  clays  is  due  to  a 
peculiarity  possessed  by  them,  easily  explicable  in  the  light  of  the 
hexite-pentite  theory,  but  otherwise  only  by  assuming  the  existence  of 
a  definite  "  clay  substance."  This  peculiarity  consists  in  the  fact 
that,  like  all  other  aluminosilicates,  clays  are  decomposed  at  high 

*  The  distribution  of  the  OH-groups  in  these  formulae  is  described  at  greater  length 
in  the  later  sections — on  Ultramarine,  Portland  Cements,  and  Porcelain  Cements. 


ACTION  OF  SULPHURIC  ACID   ON   CLAYS  107 

temperatures  and  by  some  concentrated  acids,  forming  compounds  of  the 
most  stable  type  possible,  such  as  the  following  : 

1.  Si  •  Al  •  Al  •  Si, 

2.  Si  •  Al  •  Al  •  Si,  and 

3.  S*i  •  Al  •  Al  •  Si. 

If,  for  instance,  a  clay  of  the  type 

Si  •  Al  •  SAi  -  Al  •  Si  =  6  A1203  •  18  Si02 

is  treated  with  concentrated  sulphuric  acid,  it  loses  silica  or  silica 
and  alumina,  according  to  the  temperature  and  duration  of  treatment, 
forming  a  compound  of  one  of  the  three  types  just  mentioned. 

This  is  also  shown  by  the  researches  of  C.  Bischof  218  (see  Appendix, 
'  Clays  '  —  D),  who  was  one  of  the  first  to  study  the  action  of  sulphuric 
acid  on  the  following  clays  : 

1.  m  RO  •  5  R203  •  17  Si02  •  aq. 

2.  m  RO  •  5  R2O3  •  16  SiO2  •  aq. 

3.  m  RO  •  3  R203  •  12  SiO2  •  aq. 

4.  m  RO  •  5  R203  •  17  Si02  •  aq. 

5.  m  RO  •  3  R2O3  •  15  SiO2  •  aq. 

6.  m  RO  •  5  R203  •  18  Si02  •  aq. 

7.  m  RO  •  6  R203  •  12  Si02  •  aq. 

The  action  of  sulphuric  acid  may  be  represented  as  follows  : 

1  .  S'i  •  R  •  Si  •  R  •  Si  —  >  Si  •  R  •  R  •  Si", 

2.  Si  •  R  •  Si  •  R  •  Si  —  >  Si  •  R  •  R  •  Si, 

3.  Si-R-Si  ->Si-R-R-^, 

4.  Si  •  R  •  M  •  R  •  S'i  —  >  Si  •  R  •  R  •  Si, 

/Si 

5.  R-Si  ->Si-R-R-Si, 


§ 

6.  Si  •  R  •  Si  •  R  •  Si  —  >•  Si  •  R  •  R  •  Si, 

7.  Si  •  R  •  R  •  Si        —  >  Si  •  R  •  R  •  Si. 

The  above  examples  —  which  may  be  increased  indefinitely  —  show 
conclusively  that  clays  are  really  converted  into  the  highly  stable 
compounds  stated.  The  alumina-silica  ratio  is  approximately  1  :  2  — 
which  cannot  be  a  mere  coincidence  —  and  the  supposition  that  clays 
contain  a  "  clay  substance  "  separable  by  acids  —  though  erroneous  —  is 
a  very  natural  one. 

Mellor  and  Holdcroft708  consider  that  clays  are  decomposed  by 
sulphuric  acid  in  another  manner,  viz.  with  separation  of  silica  and 
the  formation  of  aluminium  sulphate.  This  view  is  highly  improbable, 
as  an  almost  constant  ratio  of  A1203  and  Si02  has  been  found  in  the 
solution  by  numerous  investigators,  and  this  constancy  is  the  founda- 
tion of  the  theory  of  the  so-called  "  clay  substance." 


108  THE   CONSTITUTION    OF  CLAYS 

Forchhammer219  appears  to  have  been  the  first  to  express  any  doubt 
as  to  the  unitary  nature  of  clays.  He  supposed  that  in  sulphuric  acid 
he  had  found  a  valuable  "  solvent  "  for  clays  and  regarded  that  portion 
which  entered  into  solution  as  "  clay  "  and  the  remainder  as  "  un- 
decomposed  felspar."  From  time  to  time,  doubts  have  been  expressed* 
as  to  the  value  of  the  so-called  "  rational  analysis,"  but  the  remarkable 
resistance  of  clays  to  strong  acids  is  the  chief  reason  why  Forch- 
hammer's  conception  of  "  clay  substance  "  is  still  maintained,  though 
modern  chemists  represent  it  by  a  different  formula. 

Forchhammer 's  theory  of  clays  is  now  of  merely  historical  interest 
and  must  be  abandoned  as  inconsistent  with  the  facts. 

[With  it,  the  rational  analysis  must  also  be  abandoned,  at  any  rate  as  far  as  the 
usual  interpretation  of  its  results  are  concerned,  f] 

There  is,  at  the  present  time,  no  fact  known  which  is  not  compatible 
with  the  unitary  chemical  nature  of  clays  as  opposed  to  the  view  that 
they  are  mixtures. 

[This  statement  must  be  taken  to  refer  to  "  purified  "  clays,  for  many  materials 
are  commonly  termed  "  clay  "  which  obviously  contain  other  constituents.  Thus 
"  boulder  clay  "  contains  limestone  and  other  stones,  loams  contain  sand  which  may 
be  removed  by  simple  washing,  and  many  "  clays  "  contain  rock-debris  of  a  nature 
clearly  distinct  from  clay.  Unfortunately,  some  of  these  obviously  "  non-clay " 
materials  are  in  so  fine  a  state  that  they  cannot  be  perfectly  separated  by  elutriation 
or  similar  mechanical  processes.  It  does,  however,  appear  to  be  true  that,  quite  apart 
from  the  hexite-pentite  theory,  the  essential  constituents  of  clays  are  definite  alumino- 
silicates.] 

Minerals  of  the  allophane  group  are  characterised  by  the  ease  with 
which  they  are  decomposed  by  acids.  Other  hydro-aluminosilicates, 
including  several  clays,  are  only  readily  decomposed  by  dilute  acids 
after  they  have  been  heated  very  strongly.  The  reason  for  this 
difference  in  the  behaviour  of  substances  which,  according  to  the 
authors'  hexite-pentite  theory,  are  analogous,  can  only  be  explained 
in  the  following  manner  : 

"  Disdynamised  "  and  "  Dynamised  "  Compounds 

It  has  been  shown,  in  connection  with  the  tungstates  (p.  95),  that 
the  presence  of  a  base  weakens  the  bonds  in  the  ring-radicles  of  com- 
plexes. Thus,  tungstovanadates  with  a  small  content  of  base  are  not 
decomposed  by  acids,  but  in  those  richer  in  base  a  precipitate  of  tungstic 
acid  readily  forms  when  they  are  treated  with  acids.  The  bonds 
between  the  ring-radicles  of  complex  substances  may  also  be  weakened 
in  other  ways,  such  as  by  an  increase  in  the  proportion  of  "  water  of 
constitution  "  or  "  water  of  crystallisation  "  or  by  subjecting  the 
substance  to  a  high  temperature. 

Compounds  in  which  the  chemical  relationship  between  the  ring- 

*  Seger  investigated  this  subject  and  recommended  it — under  the  title  of  "rational 
analysis  " — for  relatively  pure  clays,  but  found  it  unsatisfactory  for  the  clays  used  for 
the  manufacture  of  bricks,  tiles,  cement,  etc.  Brongniart  and  Malaguti220  did  not 
question  the  "  undoubted  advantages  of  rational  analysis,"  but  saw  in  the  results 
obtained  an  uncertainty  "  which  compels  us  to  draw  conclusions  with  very  great  care." 

f  Additions  and  comments  by  the  translator  which  cannot  conveniently  be  in- 
serted as  footnotes  are  printed  in  smaller  type. 


EFFECT  OF  HEAT  ON   CLAY  109 

radicles  is  weakened  by  these  means  so  that  the  substance  becomes 
readily  decomposable  by  dilute  acids,  are  said  to  be  "  disdynamised  " 
in  order  to  distinguish  them  from  the  "  dynamised  "  substances  which 
resist  the  action  of  dilute  acids. 

The  reason  why  minerals  of  the  allophane  group  are  readily 
decomposed  by  dilute  acids  is  now  clear  :  in  them  the  relationship 
between  the  silicon-  and  aluminium-hexites  has  been  weakened  by 
the  presence  of  a  high  proportion  of  combined  water. 

Clays  usually  contain  only  "  water  of  constitution  "  ;  on  heating  to 
vitrification  they  are  disdynamised  and  then  behave  like  the  analogous 
minerals  of  the  allophane  group. 

[The  vitrification  point  of  a  clay  is  that  temperature  to  which  it  must  be  heated 
in  order  that  sufficient  fusion  may  occur  for  most  of  the  pores  in  the  clay  to  be  filled 
with  fused  matter,  yet  without  the  material  losing  its  original  shape  to  any  appreciable 
extent.  In  most  clays  there  appears  to  be  no  single  temperature  at  which  this  occurs 
to  the  exclusion  of  others  ;  the  material  becomes  vitrified  gradually  throughout  a  range 
of  temperature  which  sometimes  extends  over  400°  C.,  though  some  clays  vitrify  com- 
pletely in  a  very  few  moments  after  the  fusion  of  some  of  their  constituents  has  com- 
menced. This  property  of  vitrification  is  extremely  important  in  the  technical  appli- 
cation of  clays ;  further  information  about  it  will  be  found  in  the  translator's  "  British 
Clays,  Shales,  and  Sands."706  It  is,  however,  possible  that  this  range  of  vitrification  is 
due  to  difficulties  in  maintaining  a  perfectly  constant  temperature  for  a  sufficiently  long 
time.  If,  as  Doelter  has  suggested,  the  vitrification  point  is  definable  as  that  at  which 
fusion  is  first  observed  to  commence,  and  if,  further,  in  accordance  with  A.  Stock's 
investigations,  which  showed  that  the  vitrification  point  and  the  true  melting  point 
of  a  silicate  are  identical  and  that  vitrification  occurs  on  heating  perfectly  pure  crystal- 
line chemical  compounds,  then  it  should  be  possible  to  produce  a  completely  vitrified 
mass  by  maintaining  the  material  for  a  sufficiently  long  time  at  the  lowest  temperature 
at  which  fusion  can  be  observed  to  occur.  The  cost  and  difficulty  of  doing  this  with 
reasonably  large  masses  of  clay  are  very  great,  as  the  conductivity  of  the  material  is 
so  low,  but  so  far  as  the  translator's  own  experiments  go,  and  in  so  far  as  he  has  been 
able  to  find  other  similar  experimental  evidence,  there  are  good  reasons  for  believing 
that  the  apparent  range  of  vitrification  or  of  fusion  is  merely  a  result  of  the  extra- 
ordinarily low  conductivity  of  clay  and  of  the  high  temperature  at  which  fusion  occurs. 
Could  clays  be  fused  at  temperatures  as  easily  observed  as  those  used  in  studying  the 
melting  points  of  many  organic  compounds,  there  is  great  probability  that  pure  clays 
would  be  found  to  have  a  sharply  defined  melting  point.  As  it  is,  the  only  means  of 
effecting  vitrification  or  fusion  within  a  reasonably  short  time  consists  in  raising  the 
temperature  considerably  above  that  which  would  be  necessary  if  time  were  no  con- 
sideration. In  other  words,  the  term  "  range  of  vitrification  "  indicates  a  practical 
experience  even  if  it  may  lead  to  the  erroneous  assumption  that  clays  differ  from 
other  definite  chemical  compounds  in  not  having  a  sharp,  well-defined  melting 
point.] 

In  order  to  understand  the  nature  of  the  state  of  disdynamisation 
produced  when  clays  are  heated  to  vitrification,  it  is  necessary  to 
assume  that  oxygen  has  two  kinds  of  valency — primary  and  secondary 
— and  that  the  bonding  of  the  ring-radicles  is  due  to  both  the  primary 
and  the  secondary  valencies  of  oxygen.  If  the  proportion  of  base  or 
combined  water  in  the  compound  is  increased,  the  secondary  valencies 
are  set  free  either  partially  or  completely  according  to  the  proportion 
of  base  or  water.  On  increasing  the  temperature,  the  bound  secondary 
affinities  are  also  partially  or  completely  liberated,  according  to  the 
temperature  to  which  the  substance  is  heated. 

It  is  conceivable  that  as  soon  as  the  secondary  valencies  are  set 
free,  a  looser  bond  must  exist  between  the  ring-radicles  of  the  complexes 
concerned. 


110  CONSEQUENCES   OF  THE   H.P.   THEORY 

At  the  vitrification  temperature,  the  nascent  secondary  oxygen 
valencies  of  the  disdynamised  clay  molecules  at  once  begin  to  be 
liberated,  and  this  may  readily  lead  to  the  formation  of  polymerisation 
products.  If  the  temperature  increases,  the  liberation  also  increases, 
and  when  it  is  complete  the  whole  of  the  material  is  reduced  to  a 
molten  state.  It  is  clear  that  as  the  temperature  rises,  the  polymerisa- 
tion increases,  and  this  is,  necessarily,  followed  by  an  increase  in 
density.  When  the  mass  is  completely  fused,  the  point  of  maximum 
density  will  have  been  reached. 

[Some  highly  interesting  investigations  by  R.  Rieke707  on  the  temperature  at 
which  certain  clays  lose  their  "  combined  water  "  are  worth  special  attention.  This 
investigator  followed  Le  Chatelier's  observation  that  if  a  sample  of  kaolin  is  slowly 
heated  there  is  a  point  at  which  the  temperature  ceases  to  rise  for  some  minutes,  after 
which  it  again  rises  steadily.  If  the  temperature  and  duration  of  the  heating  are 
plotted  as  ordinates  and  abscissae,  the  graph  produced  will  show  a  marked  flattening 
about  500°  C.  Rieke  examined  10  kaolins,  8  plastic  fireclays,  6  non-refractory  clays 
(red-burning),  and  2  shales,  and  in  each  case  he  found  that  a  marked  absorption  of 
heat  occurred  and  was  shown  by  the  flattening  of  the  graph  at  a  temperature  of  500° 
to  580°  C.  The  purer  the  clays,  the  more  noticeable  is  this  break  in  the  rise  of  tem- 
perature. 

In  clays  containing  much  free  quartz  the  absorption  of  heat  is  obscured  by  the 
reactions  which  the  quartz  undergoes  at  the  temperatures  mentioned,  and  the  more 
complex  graphs  of  the  impure  clays  may  be  further  affected  by  the  reactions  of  other 
compounds  present. 

Rieke  also  found  that  the  loss  of  water  corresponded  to  the  flattening  of  the  heat- 
ing curve;  a  notable  evolution  of  water  commences  at  450°  C.,  and  almost  the  whole 
of  the  water  is  removed  at  a  temperature  of  550°  to  600°  C.,  though  for  its  complete 
expulsion  prolonged  heating  at  a  higher  temperature  appears  to  be  necessary.  The 
rate  of  evolution  of  water  is  not  regular,  and  diminishes  rapidly  when  most  of  the 
water  has  been  removed.  It  is  increased  by  reducing  the  pressure  of  the  air  surround- 
ing the  clay. 

Mellor  and  Holdcroft708  have  independently  confirmed  Rieke's  observations  with 
respect  to  china  clay,  and  have  concluded  that  the  "  china  clay  molecule  "  must  have 
its  OH-groups  placed  symmetrically.  They  accept  a  slight  modification  of  Groth's 
formula,*  viz.  : 


HO       HO 

More  recently,  Mellor  has  examined  crystalline  kaolinite  in  a  similar  manner  and 
finds  its  behaviour  is  identical  with  that  of  the  purest  Cornwall  china  clay. 

Unlike  the  authors  of  the  present  volume,  Mellor  and  Holdcroft  conclude  that  the 
"  clay  molecule  "  is  decomposed  into  its  constituent  oxides — alumina  and  silica — at 
500°  C.,f  and  consider  that  the  formation  of  sillimanite  at  higher  temperatures  (1200°  C.) 
is  a  confirmation  of  this  in  accordance  with  the  equation  : 

A1203  +  Si02  =  Al2Si05. 

They  agree  that  polymerisation  of  the  alumina  occurs  (with  evolution  of  heat  at 
800°  C.),  but  have  published  no  formula  for  the  polymerisation-product.  In  other 
words,  they  regard  the  latter  as  though  it  were  the  simple  non-polymerised  substance 
when  (according  to  them)  it  reacts  at  1200°  C.  with  the  silica  to  form  sillimanite. 

*  The  views  of  the  authors  of  the  present  volume  as  to  the  distribution  of  the 
OH-groups  are  described  at  greater  length  in  the  later  sections — on  Ultramarine, 
Portland  Cements,  and  Porcelain  Cements — and  the  following  formulae  are  also  criti- 
cised on  p.  116. 

t  See  p.  113. 


BURNING  CLAYS  111 

W.  Pukall710  has  suggested  the  formula  : 

OH 

HO  •  Si  •  O  •  O  •  Al  •  OH 

HO  •  Si  •  O  •  O  •  Al  •  OH 
OH 

and  in  opposition  to  all  other  writers  indicates  a  double  bond  between  the  silicon 
atoms.  From  what  has  been  stated  on  previous  pages,  however,  the  bond  between  the 
silicon  atoms  must  contain  oxygen.  The  view  that  a  direct  connection  exists  between 
the  silicon  atoms  is  also  held  by  Simmonds721,  who  studied  the  action  of  hydrogen  at 
high  temperatures  on  lead  meta-silicate,  to  which  is  usually  assigned  the  formula  : 


He  reached  the  conclusion  that  both  oxygen  atoms  cannot  occupy  similar  positions, 
and  suggested  the  following  formula  for  this  silicate  : 

—    Si Si Si    — 

O     O     O  —  O    O     O 

II  II 

R— O  O— R 

Simmonds  thus  suggests  that  the  silicon  atoms  are  connected  directly  with  each  other 
and  not  through  the  medium  of  oxygen  atoms.  Manchot  and  Keiser722  were  unable 
to  confirm  Simmonds'  observation  on  lead  silicates,  and  rightly  argue  that  silicon 
compounds  in  which  the  silicon  atoms  are  directly  connected  with  each  other  must 
evolve  hydrogen  when  treated  with  hydrofluoric  acid  and  then  with  alkali,  yet  this 
reaction  never  occurs  with  the  silicates  now  under  consideration.  Manchot723  uses 
this  argument  in  criticising  Pukall' s  formula,  and  adds  that  such  a  double  bond  would 
imply  that  kaolinic  acid  would  be  more  easily  decomposed  by  alkalies  than  by  other 
silicates  with  a  single  bond,  whereas  kaolinic  acid  is  very  resistant  to  alkalies. 

Singer724  has  also  criticised  Pukall's  formula  unfavourably  and  has  pointed  out 
that  a  double  silicon  bond,  like  a  double  carbon  bond,  is  a  source  of  weakness  in  a  com- 
pound rather  than  one  of  strength. 

The  re-combination  of  water  with  the  dehydrated  kaolin  is  also  of  interest  as 
throwing  further  light  on  the  constitution  of  the  molecule.  Mellor  and  Holdcroft  (I.e.) 
found  that  even  in  an  autoclave  at  300°  C.  under  a  pressure  of  200  atmospheres  the 
dehydrated  china  clay  only  absorbed  2-5%  of  water.  Rieke  found  that  a  Bohemian 
kaolin,  which  had  been  heated  at  500°  C.  until  all  the  water  had  been  removed,  could 
only  be  made  to  re-combine  with  1-1%  of  water.  The  very  small  proportion  of  re- 
combination which  occurs  is  a  further  proof  of  the  remarkably  high  stability  of  the 

anhydride  Si  •  Al  •  Al  •  Si,  as  pointed  out  by  the  authors  of  the  present  volume.] 


Burning  Clays 

["  Burning  "  is  a  term  used  to  indicate  the  heating  of  articles  made  of  clay  under 
industrial  conditions  in  kilns  or  ovens  in  order  to  give  them  the  characteristics  desired 
in  pottery,  bricks,  tiles,  etc.  It  differs  from  simple  heating  (or  calcination)  in  that  the 
clays  have  been  formed  into  articles  of  the  desired  shape  and  in  that  the  heating  must 
usually  be  prolonged  and  the  rise  in  temperature  must  be  very  slow  so  as  to  avoid  the 
splitting  and  cracking  of  the  goods. 

This  explanation  is  necessary,  as  the  shape  of  the  articles  and  the  speed  of  the 
heating  are  important  determinants  of  the  character  of  the  heated  material.  In 
"  burning,"  clays  are  never  supposed  to  be  heated  to  such  an  extent  as  to  cause  them 
to  fuse  sufficiently  for  loss  of  shape  to  occur.  When  this  happens  they  are  "  over- 
burned."] 

So  long  as  clays  are  regarded  as  mixtures  of  quartz,  undecomposecl 
felspar  and  "  clay  substance,"  no  satisfactory  explanation  of  what 
occurs  during  the  burning  is  possible.  The  great  difference  in  the  effect 
of  dilute  acids  on  raw  and  burned  clays  makes  it  obvious  that  some 


112  CONSEQUENCES   OF  THE   H.P.   THEORY 

definite  chemical  reactions  must  occur  during  the  burning.  The  nature 
of  these  reactions  has,  hitherto,  been  inexplicable.  From  a  "  mixture," 
all  kinds  of  simple  and  double  salts  might  be  formed,  and  these  cannot 
be  adequately  examined.  Yet  a  correct  understanding  of  the  burning 
process  is  not  only  of  academic  value,  but  of  great  practical  importance. 
Hence,  the  hexite-pentite  theory  should  be  of  great  assistance  in  in- 
dicating the  chemical  reactions  which  take  place  on  burning. 

These  reactions  may  be  stated  in  terms  of  the  Disdynamisation 
Theory  (p.  108)  as  follows  : 

1.  On  heating  a  clay  to  vitrification,  part  of  or  all  the  "  water  of 
constitution  "  is  evolved.    Secondary  valencies  of  some  of  the  oxygen 
atoms  are  set  free,  but  the  clay  itself  retains  its  unitary  chemical  nature 
and  is  not  decomposed  into  its  constituent  oxides. 

2.  If  the  temperature  exceeds  that  necessary  for  vitrification,  the 
free  valencies  liberate  themselves  and  form  polymerisation  products, 
the  clays  eventually  fusing  either  partially  or  completely.    Hence  fused 
clays  must  possess  properties  chemically  different  from  those  which 
have  been  merely  vitrified.     The  density  of  fired  clays  must  also  be 
higher  than  that  of  vitrified  clays. 

3.  Vitrified  clays  must  be  more  easily  attacked  by  acids  than  un- 
vitrified  ones. 

[This  "  consequence  "  is  erroneous,  as  explained  below.] 

[In  this  connection,  the  extensive  use  of  vitrified  (stoneware)  clays  in  the  manu- 
facture of  acids  and  in  the  construction  of  appliances  (stills,  etc.)  in  which  hot  acids 
are  used  is  important.  General  experience  appears,  at  first  sight,  to  be  in  direct  con- 
tradiction to  the  authors'  statement  in  this  paragraph,  as  vessels  made  of  clay  which 
has  been  vitrified  are  usually  found  to  be  amongst  the  most  powerful  resistants  to  all 
acids  except  hydrofluoric. 

It  is  probable,  however,  that  polymerisation  products  and  the  presence  of  these 
and  of  fused  material  of  a  highly  resistant  nature  may  be  the  cause  of  this  anomaly, 
the  term  "  vitrified  "  used  in  the  text  being  understood  to  refer  to  clays  which  have 
only  been  heated  to  the  lowest  temperature  at  which  vitrification  can  possibly  occur, 
and  not  to  a  temperature  at  which  polymerisation  products  are  formed.  If  this  is 
the  case  and  the  disdynamic  action  is  stopped  on  polymerisation  or  partial  fusion,  the 
apparent  anomaly  is  destroyed  and  the  authors'  theory  becomes  conformable  to 
general  experience.] 

The  observations  of  Mellor  and  Holdcroft708  and  others  show  that 
clay  which  has  been  heated  to  a  certain  temperature  is  (in  accordance 
with  the  theory)  more  readily  attacked  by  acids  than  that  which  has 
not  been  heated.  It  is  also  a  well-known  fact  that  on  further  heating 
at  a  still  higher  temperature  a  material  is  produced  which  is  resistant 
to  acids  (in  contradiction  to  the  theory).  Such  polymerisation  as 
occurs  will,  however,  make  the  heated  clay  resistant  to  acids.  In  this 
connection  it  must  be  remembered  that  the  polymerisation  brought 
about  by  disdynamisation  is  itself  a  dynamisation  and  so  increases  the 
resistance  of  the  material  to  chemical  influences.  The  rise  of  tempera- 
ture can,  in  fact,  only  have  a  complete  disdynamic  action  when  no 
polymerisation  occurs.  This  fact  was  overlooked  by  the  authors  until 
it  was  pointed  out  to  them  by  A.  B.  Searle,  and  this  oversight  is  the 
cause  of  the  erroneous  conclusion  reached  in  Consequence  3  of  the 
theory. 


ISOMERISM   AND   POLYMERISATION   OF   KAOLIN     113 

4.  The  so-called  ''decomposition"  (p.  107)  by  concentrated  acids 
is  merely  a  disdynamisation. 

The  observation  of  R.  Rieke  that,  on  burning  clays,  their  tempera- 
ture does  not  rise  steadily,  but  remains  constant  for  a  long  time,  not- 
withstanding the  increased  temperature  of  the  kiln,  may  be  explained 
in  terms  of  the  new  theory  if  the  constant  temperature  occurs  at  the 
sintering  point  of  the  clay. 

The  statement  made  by  Desch  that  clays  heated  to  700°  can  easily 
add  calcium  silicate,  calcium  aluminate,  or  calcium  hydrate  may  be 
explained  by  the  new  theory  of  burning  stated  below. 

The  behaviour  of  the  silicate  molecule  towards  acids  also  depends  on 
the  number  of  aluminium  hydro xyl  groups  in  the  molecule.  This  must 
always  be  borne  in  mind  when  studying  this  subject,  and  is  therefore 
dealt  with  exhaustively  in  the  following  chapter. 

There  can  be  no  doubt  that  the  rise  in  temperature  exerts  a  dis- 
dynamising  action  on  clays,  and  that  in  consequence  of  this  action 
molecular  changes  are  produced  in  addition  to  such  polymerisation  as 
may  occur.  This  is  particularly  the  case  with  kaolin,  as  will  be  seen  on 
reading  the  following  chapter.  If  the  theory  is  extended  in  this 
manner  it  will  be  found  to  be  in  complete  agreement  with  the  observed 
facts. 

It  is  not  then  necessary,  as  Mellor  and  Holdcroft  suggest,  to 
assume  that,  on  heating,  clays  are  decomposed  into  free  silica  and 
alumina  and  that  a  re-combination  of  these  oxides  occurs  on  further 
heating. 

The  investigations  of  Richter,  Bischof,  Jochum,  Rieke  and  others 
have  shown  that  the  fusing  point  of  clays  is  greatly  influenced  by  the 
impurities,  such  as  quartz,  alkalies,  etc.,  present.  A  theory  of  burning 
to  be  satisfactory  must  take  this  into  consideration. 

This  consideration  of  the  burning  process  may  be  allowed  to  suffice 
as  an  explanation  of  the  decomposition  of  slightly  heated  clay  by 
acids  and  its  greater  resistance  after  heating  at  a  higher  temperature. 
At  the  same  time,  this  theory  of  burning  leads  to  no  conclusions 
with  regard  to  certain  properties  of  kaolin  which  are  described  in 
the  following  chapter.  It  may,  therefore,  be  necessary  to  modify 
the  application  of  the  Disdynamisation  theory  to  burning,  as 
further  facts  are  observed. 


The  Isomerism  and  Polymerisation  of  Kaolin 

From  the  formula  6  H20  •  6  A1203  •  12Si02  (kaolin)  two  isomeric 
substances  may  be  formed.  * 

*  If  a  rule  is  made  to  name  the  central  core  first  and  then  the  side  chains,  the 
acid  A  may  be  termed  di-h-alumino-di-h- silicic  acid,  and  the  acid  S  di-h-silico-di-h- 
aluminic  acid.  Hence  the  salts  of  the  ,4-acid  and  all  silicates  with  a  central  aluminium 
core  may  be  termed  aluminosilicates,  whilst  the  salts  of  the  $-acid  and  all  compounds 
with  a  central  silicon  core  may  be  termed  silicoaluminates. 

I 


CONSEQUENCES  OF  THE   H.P.  THEORY 

III  I       I       I       I 


114 


Al  I  Si  j  Si    Al  I 

I        I        I        I 
A.  S. 

A  number  of  derivatives  of  these  two  acids  in  which  pentites  replace 
hexites  are  theoretically  possible  : 

y\/\/\/v        _AAA/'\ 


Si    Al    Al    Si 


and          I  Al  j  Si  I  Si  I  Al 

— —  L 


\/ 


A'. 


S'. 


Si      ~    and 


In  accordance  with  the  foregoing  nomenclature  these  acids  may  be 
termed  : 

A' Di-p-alumino-di-h-silicic  acid. 

A" Di-h-alumino-di-p-silicic  acid. 

|§' Di-p-silico-di-h-aluminic  acid. 

S" Di-h-silico-di-p-aluminic  acid. 

The  acids  with  central  aluminium  rings  may  be  shortly  termed  a- 
kaolinic  acids,  and  those  with  central  silicon  rings  as  s-kaolinic  acids. 

Two,  three  or  more  molecules  of  the  acids  A,  A',  or  A"  and  of  the 
acids  S,  S'  or  S"  may  lose  certain  molecules  of  water  and  then  unite  to 
form  polymerisation  products.  Thus,  the  following  compounds  are 
possible  : 

/\/ 


Si 


Al    Al 


Si 


Si     Al    Al 

\AA 

A2 


Si 


ISOMERISM  AND  POLYMERISATION  OF  KAOLIN      115 


/\/\/\/\ 


i/x/YYx 

I  Al     Si  I  Si  I 

\/\/\/\ 

III! 

/\/\/\/ 

I  Al  |  Si  I  Si  |  Al 

\/\/\/\ 


etc.  etc. 


On  polymerisation,  separation  of  water  can  only  occur  in  two 
analogous  rings,  as  in  the  centre  of  the  S'2  or  the  side  rings  of  the  S"2 
compounds. 

Between  the  a-  and  s-kaolinic  acids  and  their  salts  there  must  be  a 
genetic  relationship,  as  they  can  be  converted  into  each  other.  This 
transformation  may  be  represented  as  follows  : 

I.  Conversion  of  the  a-kaolinic  acid  into  s-kaolinic  acid  : 


a-kaolinic  acid. 


a-kaolinic  acid. 


a-kaolinic  acid. 


s-kaolinic  acid.  3-kaolinic  acid. 

II.  Conversion  of  the  s-kaolinic  acid  into  a-kaolinic  acid 


Al    Si     Si    Al 


a-kaolinic  acid. 


5-kaolinic  acid. 


«-kaolinic  acid. 


a-kaolinic  acid. 


a-kaolinic  acid. 


116  CONSEQUENCES   OF  THE   H.P.   THEORY 

In  an  analogous  manner  the  polymerised  a-kaolinic  acids  may  be 
converted  into  polymerised  s-kaolinic  acids  and  vice  versa. 

In  the  chapter  on  Ultramarines  and  Porcelain  cements  two  kinds 
of  hydroxyl  groups  in  kaolinic  acids  are  described  :  termed  a-  and  s- 
hydroxyls,  respectively.  The  former — the  hydroxyls  of  the  aluminium 
rings — are  acidophillic,  and  the  latter — the  hydroxyls  of  the  silicon 
rings — are  basophillic.  The  kaolinic  acids — both  simple  and  poly- 
merised— appear  to  contain  more  s-hydroxyls  and  less  a-hydroxyls  ; 
the  s-kaolinic  acids,  on  the  contrary  (both  simple  and  polymerised), 
contain  more  a-hydroxyls  and  less  s-hydroxyls. 

These  variations  in  the  number  of  a-  and  s-hydroxyls  of  the  a-  and 
s-kaolinic  acids  must  result  in  these  acids  having  a  different  relationship 
to  other  acids  and  a  different  solubility  in  acids.  The  more  a-hydroxyls 
a-kaolinic  acid  contains,  the  more  soluble  must  it  be  in  acids,  or  in  other 
words,  the  s-kaolinic  acids  must  usually  be  more  soluble  in  acids  than 
the  analogous  isomers  or  a-kaolinic  acids. 

As  the  degree  of  polymerisation  must  diminish  with  a-hydroxyls, 
it  follows  that,  cceteris  paribus,  the  polymerised  kaolinic  acids  must  be 
less  soluble  in  acids  than  the  non-polymerised  ones.  From  the  theory  it 
follows  that  the  anhydrides  of  the  a-kaolinic  acids  have  the  lowest 
degree  of  solubility  in  acids,  and  therefore  the  greatest  resistance  to 
acids.  If  the  plasticity  of  clays  is  a  function  of  the  water  of  constitution 
(see  p.  65)  it  follows  that  : 

1.  The  a-kaolinic  acids  can  generally  have  a  higher  degree  of 
plasticity  than  the  s-kaolinic  acids,  as  the  former  contain  more  water 
of  constitution. 

2.  The  polymerised  kaolinic  acids  have,  cceteris  paribus,  a  lower 
plasticity  than  the  non-polymerised  ones. 

The  a-  and  s-kaolinic  acids  must  also  differ  from  each  other  in 
physical  characters,  such  as  density,  resistance  to  reagents,  etc.,  as 
well  as  in  chemical  structure.  There  is  another  interesting  consequence 
of  the  new  theory  as  applied  to  kaolinic  acids : — In  the  salts  of  the 
kaolinic  acids,  such  a  compound  as 

I      II     II      ! 

'\/\_ 


8  Na20  •  6  A1203  •  12  Si02, 
Normal  sodium  s-kaolinate. 

must  have  the  sodium  united  to  the  silicon  ring  (i.e.  s-sodium) 
more  strongly  than  the  a-sodium  attached  to  the  aluminium  ring  ; 
i.e.  in  this  compound  half  the  sodium  must  be  more  strongly  united 
than  the  remainder.  It  is  also  probable,  on  a  priori  grounds,  that  this 
sodium  salt  will  behave  differently  towards  different  acids  ;  the 
stronger  acids  can  remove  the  whole  of  the  sodium  (both  a-  and  s- 
sodium),  but  the  weaker  acids  can  only  remove  the  a-sodium. 


PUKALUS  EXPERIMENTS  ON  KAOLIN 


117 


The  Hexite-Pentite  Theory  and  the  Facts 

The  available  experimental  material  is  in  entire  agreement  with 
the  theory  developed  in  the  preceding  pages.  In  this  connection  the 
work  of  (a)  W.  Pukall710  and  (b)  Mellor  and  Holdcroft708  on  kaolinisa- 
tion  is  of  special  value. 


The  Study  of  Kaolinisation  by  W.  Pukall710 

W.  Pukall  has  endeavoured  to  prepare  kaolin  synthetically,  and 
from  a  mixture  of  18-75  of  quartz,  24-38  of  aluminium  hydrate,  150  of 
caustic  soda  and  75  c.c.  water  heated  in  a  silver  crucible  until  the 
mass  became  stiff,  he  obtained  a  product  which,  on  washing,  yielded  a 
white,  crystalline  substance  which  melted  at  Seger  cone  7  (about  1270°), 
i.e.  the  temperature  at  which  salt  glazed  ware  is  glazed. 

Zettlitz  kaolin  or  English  china  clay  when  melted  with  ten  times 
its  weight  of  common  salt  at  950°  C.  evolved  water  and  hydrochloric 
acid  and  combined  with  sufficient  soda  (28%)  to  be  comparable  to 
Na2O  •  A1203  •  2  Si02.  Both  these  kaolins  are  converted  into  a  crystal- 
line substance. 

Multiplying  the  formula  just  mentoned  by  6,  the  following  com- 
pound : 

6  Na20  •  6  A1203  •  12  Si02  •  12  H20, 

is  formed  ;  it  may  be  the  salt  of  either  an  a-  or  an  s-kaolinic  acid. 

From  Pukall's  investigations  it  appears  highly  probable  that  the 
salt  he  obtained  is  a  polymerised  sodium  s-kaolinic  acid  of  the  following 
formula  : 


12H90 


I 
6  Na20  •  6  A1203  •  12  Si02  •  12  H2O. 

As  the  ratio  A1203  :  Si02  in  the  salt  obtained  by  Pukall  is  the  same 
as  that  in  kaolin,  he  endeavoured  to  remove  the  Na2O  and  to  obtain 
the  free  acid,  i.e.  the  "  kaolin."  For  this  purpose  he  used  two  methods  : 
by  treatment  with  (a)  carbonic  acid  and  (b)  hydrochloric  acid.  The 
results  of  these  two  experiments,  whilst  in  agreement  with  the  H.P. 
theory,  were  quite  different  :  the  carbonic  acid,  as  a  weak  acid,  only 
removes  the  a-sodium  and  converts  the  Si-hexites  into  pentites  ;  the 


118 


CONSEQUENCES  OF   THE   H.P.   THEORY 


hydrochloric  acid,  as  a  strong  acid,  removes  the  whole  of  the  a-sodium 
and  half  the  s-sodium,  as  may  be  seen  from  the  following  : 

a.  THE  BEHAVIOUR  OF  PUKALL'S  SODIUM  S-KAOLINATE  TOWARDS 

CARBONIC  ACID 

The  sodium  di-s-kaolinate  (6  Na20  •  6  A1203  •  12  Si02  12  H20) 
of  the  above-mentioned  structure  was  heated  in  a  Soxhlet's  apparatus 
for  264  hours  with  carbonic  acid  in  order  to  remove  the  soda,  and  by 
this  means  Pukall  obtained  a  substance  corresponding  to  the  formula 


12H20 


2  Na20  •  4  H20  •  10  Si02  •  6  A1203  •  12  H20. 

The  analyses  made  confirm  this  formula  : 

Na20        H20        A1203         SiO2 

Calculated    7.63        17.76        37.68        36.94 

Found 7.10        19.95        37.49        36.82 

The  carbonic  acid  converts  the  Si-hexite  into  Si-pentite  as  already 
described.  The  feebly  acid  carbonic  acid  can  only  remove  the  acido- 
phillic  aluminium  rings,  and  not  the  strongly  basophillic  Si-rings. 

b.  THE  BEHAVIOUR  OF  PUKALL'S  SODIUM  S-KAOLINATE  TOWARDS 
HYDROCHLORIC  ACID 

Pukall  also  endeavoured  to  remove  the  Na20  in  the  sodium  salt 
above  mentioned  by  means  of  a  stronger  acid,  for  which  purpose  he 
selected  hydrochloric  acid.  The  sodium  salt  dissolves  in  this  acid 
and  is  obtained,  on  treatment  with  ammonia,  in  the  form  of  a 
voluminous  white  precipitate  corresponding  to 


Calculated 
Found  . 


(R20  4  H20 
0.5  Na2O 

...   1.77 
.  2.15 


0.5  (NH4)20 
1.48 
1.26 


12  SiO2 
12  SiO2 

41.16 

42.07 


6A1203)2 
6  A1203 
34.99 
36.33 


32  H20. 
20  H20. 

20.58 
20.00 


PUKALL'S   EXPERIMENTS   ON   KAOLIN  119 

Pukall  did  not  determine  the  proportion  of  Na20  and  (NH4)20  and 
suggested  the  following  formula  : 

3H20  A1203  2Si02 

Calculated 19.57  36.91  43.47 

Found   20.00  36.93  42.07 

The  hydrochloric  acid,  being  a  strong  acid,  removes  some  base  from  the 
sodium  salt,  yet  a  small  proportion  of  the  base  still  remains.  It  is 
probable  that  the  hydrochloric  acid  removes  half  the  s-sodium  ;  the 
remainder  being  replaced  by  NH4. 

It  has  already  been  shown  that  the  chemical  and  physical  properties 
of  any  s-kaolinic  acid  must  differ  from  those  of  any  a-kaolinic  acid,  and 
an  acid  s-kaolinate  must  differ  still  more  widely  from  "  kaolin  "  (a- 
kaolinic  acid).  As  a  matter  of  fact,  Pukall  has  proved  that  kaolin  is 
different  from  the  kaolinate  inasmuch  as  the  former  only  loses  its  water 
on  heating  to  redness,  but  the  latter  parts  with  half  its  water  at 
temperatures  below  350°  C.  and  the  remainder  on  heating  to  redness. 
Other  properties  of  these  two  substances  also  confirm  the  view  that 
they  require  different  structural  formulae.  Kaolin,  for  example,  is 
very  plastic  on  account  of  the  many  OH-groups  it  contains.  The 
number  of  OH-groups  in  the  acid  kaolinate  is  much  less  and  part  of 
them  are  replaced  by  basic  groups.  Hence,  it  is  not  surprising  that 
Pukall  should  find  this  salt  to  be  less  plastic  than  kaolin.*  When 
PukalTs  salt  is  mixed  with  quartz  and  felspar  it  forms  a  very  lean 
mixture,  and  on  heating  this  to  1370°  a  beautiful,  white,  translucent 
porcelain  is  produced.  If  the  same  salt  is  mixed  with  free  silica  and 
alumina  the  mixture  is  not  plastic,  though  kaolin,  when  similarly 
treated,  retains  its  plasticity.  Moreover,  this  mixture  does  not  produce 
a  true  porcelain  on  burning. 

Pukall  has  also  prepared  the  above-mentioned  sodium  salt  of 
s-kaolinic  acid  by  another  method.  On  boiling  and  then  fusing  kaolin 
with  caustic  soda  and  a  little  hydrated  alumina,  and  then  washing  the 
product,  a  white  crystalline  mass  is  obtained  which  Pukall  has  shown 
to  be  the  above-mentioned  sodium  s-kaolinate.  This  method  is  of 
great  theoretical  importance,  as  it  shows  a  definite  genetic  relationship 
must  exist  between  the  a-kaolinic  acid  and  the  s-kaolinic  acid  ;  one 
being  converted  into  the  other  under  certain  conditions.  This  agrees 
with  the  results  obtained  by  Mellor  and  Holdcroft  and  discussed  in  the 
next  section. 

Pukall  has,  further,  made  the  interesting  discovery  that  if  silica  and 
alumina  are  heated  with  an  excess  of  a  very  strong  alkali  solution  the 
compound  produced  (#A1203  •  2#SiO2)  always  has  the  same  molecular 
ratio  of  alumina  and  silica,  no  matter  whether  the  silica  and  alumina 
are  free  or  in  a  combined  state. 

*  For  notes  on  the  relationship  between  plasticity  and  chemical  constitution,  see 
page  133. 


120 


CONSEQUENCES   OF  THE   H.P.   THEORY 


II 
The  Study  of  Kaolin  by  Mellor  and  Holdcroft708 

Mellor  and  Holdcroft  have  studied  the  structure  of  kaolin  by 
means  of  the  purest  china  clay  obtainable,  this  kaolin  having  a  com- 
position approximating  very  closely  indeed  to  the  formula  : 

A1203  •  2  Si02  •  2  H20. 

The  result  of  their  investigations  leads  to  the  conclusion  that  in  all 
probability  china  clay  is  an  a-kaolinic  acid  with  a  structure  represented 
by  the  formula  *  : 

II      I       I      II 

Si 


2  H20  •  6  A1203  •  12  SiO2  •  10  H20. 

This  a-kaolinic  acid  is  converted  on  heating  to  500-600°  C.  into  a 
derivative  of  s-kaolinic  acid,  as  shown  in  the  following  diagram  : 


At  a  higher  temperature  (800-900°  C.)  the  s-kaolinic  anhydride  is  poly- 
merised with  a  liberation  of  heat,  and  at  a  temperature  of  1100-1200° 
the  polymeric  anhydride  of  the  s-acid  is  converted  into  a  polymeric 
anhydride  of  the  a-kaolinic  acid  with  absorption  of  heat. 

In  this  way  the  genetic  relationship  between  the  6--  and  the 
a-kaolinic  acid  previously  discovered  by  Pukall  is  confirmed. 

The  changes  just  mentioned  are  based  on  the  following  con- 
siderations :  — 

1.  The  heating  curve  plotted  by  Mellor  and  Holdcroft  for  pure 
kaolin  shows,  at  temperatures  above  500°  C.,  a  reduction  in  the  rate 
at  which  the  temperature  rises,  and  this  is  doubtless  due  to  the  occur- 
rence of  an  endothermic  or  heat-absorbing  reaction.  At  900°  C.  a 
feeble  exothermic  reaction  occurs,  and  between  1000°  and  1200°  another 
strong  endothermic  reaction  takes  place.  These  three  "  critical 
temperatures  "  are  due  to  f  :  — 

(a)  The  conversion  of  the  a-kaolinic  acid  into  the  anhydride  of 
•s-kaolinic  acid. 

(b)  The  polymerisation  of  the  anhydride  of  the  s-kaolinic  acid. 

(c)  The  conversion  of  the  polymerised  anhydride  of  the  s-kaolinic 
acid  into  a  polymerised  anhydride  of  the  a-kaolinic  acid. 

*  Mellor  and  Holdcroft's  formula  is  given  on  p.  110. 

t  Mellor  and  Holdcroft's  interpretation  of  these  results  is  given  on  p.  122. 


MELLOR  &  HOLDCROFrS  EXPERIMENTS  ON  KAOLIN 


2.  If  this  conversion  of  the  a-kaolinic  acid  into  an  anhydride  of 
the  s-kaolinic  acid  really  does  take  place  at  a  temperature  of  500-600°C. 
as  stated  above,  it  follows  that  the  product  formed  by  heating  kaolin 
to  this  temperature  must  be  more  readily  soluble  than  the  original 
kaolin.     This  interesting  consequence  of  the  H.P.  theory  has  been 
independently  and  experimentally  confirmed  by  Mellor  and  Holdcroft, 
who  found  that  the  dehydrated  kaolin  is  more  active  than  the  kaolin 
from  which  it  was  prepared,  and  its  solubility  in  acetic,  hydrochloric 
and  nitric  acids  is  greater  than  that  of  the  unburned  kaolin. 

It  is  probable  that  the  anhydride  of  the  s-kaolinic  acid  formed  at 
600°  C.  becomes  partially  hydrated  when  under  the  influence  of  these 
acids,  and  the  acidophillic  OH-groups  (the  a-OH-groups)  thus  formed, 
and  twice  as  numerous  as  the  OH-groups  in  the  a-kaolinic  acid  mole- 
cule, will  make  the  product  more  closely  related  to  acids  and  will 
simultaneously  increase  its  solubility  in  acids. 

3.  A  glance  at  the  structural  formulae  of  the  simple   and   poly- 
merised a-  or  5-kaolinic  acids  shows  that  :  — 

(a)  The  polymerised  anhydrides  of  the  a-  and  s-kaolinic  acids  must 
have  a  greater  resistance  to  acids  than  those  which  are  not  poly- 
merised. 

(b)  The  greatest  resistance  to  acids  must  be  shown  by  the  anhy- 
drides of  the  polymerised  a-kaolinic  acids,  and 

(c)  The  s-kaolinic  acids  and  their  anhydrides  must  split  off  alumina 
more  readily  than  silica,  when  treated  with  acids. 

These  consequences  of  the  H.P.  theory  are  all  confirmed  by  Mellor 
and  Holdcroft  's  experiments  ;  the  following  being  of  special  interest  :  — 

Samples  of  china  clay,  which  had  been  maintained  at  various 
temperatures,  were  shaken  mechanically,  with  hydrochloric  acid  of 
specific  gravity  1-165  diluted  with  an  equal  volume  of  water,  for  two 
hours,  and  the  proportions  of  alumina  and  silica  dissolved  were  then 
determined.  Pure  hydrated  alumina  and  pure  hydrated  silica  were 
similarly  treated.  The  results  are  shown  in  the  following  Table  :  — 


Kaolin. 

Alumina. 

Silica. 

Tempera- 
ture. 

Loss  on 
Heating. 

Soluble  Matter. 

Loss  on 
Heating. 

Soluble 

Matter. 

Loss  on  Heating. 

Soluble 
Matter. 

% 

SiO,  %. 

AJ.O,  % 

% 

% 

% 

% 

100° 

12.64 

0.08 

0.12 

16.00 

2.60 

600° 

1.37 

0.16 

0.16 

2.45 

42.96 



1.36 

700° 

0.62 

0.12 

0.98 

2.41 

20.40 



1.36 

800° 

0.56 

0.12 

0.68 

1.58 

7.84 

1.24 

1.12 

900° 

0.23 

0.12 

0.20 

1.65 

5.92 

0.43 

0.76 

1000° 

0.25 

0.06 

0.16 

0.05 

0.00 

0.05 

0.68 

(at  1200°) 

122  CONSEQUENCES   OF  THE   H.P.   THEORY 

It  will  be  observed  that  the  solubility  of  the  alumina  in  the  china 
clay  after  heating  to  600°  is  only  slightly  higher  than  that  in  the  clay 
heated  to  100°.  It  appears  as  if  the  conversion  of  the  a-kaolinie  acid 
into  s-kaolinic  acid  commences  at  this  temperature.  At  700°  there  is  a 
notable  increase  in  the  proportion  of  soluble  alumina  ;  at  higher 
temperatures  the  solubility  of  the  alumina  appears  to  diminish  so  that 
at  8QO°  C.  it  is  only  0-68  ;  at  900°  it  is  still  lower,  and,  at  1000°,  the 
solubility  of  both  silica  and  alumina  is  very  small.  The  solubility  of 
the  alumina  in  china  clay  does  not  agree  entirely  with  the  conclusions 
previously  expressed  (see  Section  I,  p.  120)  in  which  it  was  stated  that 
the  conversion  of  the  a-kaolinic  acid  into  the  anhydride  of  the 
s-kaolinic  acid  occurs  at  500-600°  C.,  but  the  above  Table  clearly  offers 
a  general  confirmation  of  the  theory  inasmuch  as  it  shows  an  increased 
solubility  in  hydrochloric  acid  as  the  temperature  to  which  china  clay 
is  heated  is  increased. 

4.  The  specific  gravity  of  the  s-kaolinic  acids  must,  clearly, 
differ  from  that  of  the  a-kaolinic  acids  and  the  investigations  of  Mellor 
and  Holdcroft  have  shown  that  this  is  the  case,  the  specific  gravity 
diminishing  as  the  conversion  of  the  a-  into  the  s-kaolinic  acid  takes 
place.  The  Table  below  shows  that  at  600°  the  specific  gravity  of  the 
clay  is  distinctly  lower  than  at  110°. 

At  high  temperatures  the  polymerisation  which  occurs  and  the 
formation  of  the  polymerised  anhydride  of  a-kaolinic  acid  must 
necessarily  result  in  a  series  of  increases  in  the  specific  gravity  of  the 
material.  Mellor  and  Holdcroft  have  (without  recognising  the  true 
nature  of  the  compounds  with  which  they  were  dealing)  determined 
the  specific  gravity  of  the  various  a-  and  s-kaolinic  acid  derivatives,  as 
shown  in  the  following  Table  : 


Temperature. 


110 

600 
700 
800 
900 
1000 


Specific  Gravity. 

2.615 
2.473 

2.469 
2.497 
2.560 
2.734 


Hence  the  various  consequences  of  the  H.P.  theory  as  applied  to 
the  kaolinic  acids  are  in  complete  agreement  with  the  facts. 

Mellor  and  Holdcroft  have  endeavoured  to  explain  the  three 
critical  temperatures  (500-600°,  800-900°,  and  1100-1200°),  mentioned 
above,  which  are  recognisable  on  heating  kaolin,  and  the  abnormal 
behaviour  of  dehydrated  kaolin  to  wards  acids,  on  the  assumption  that 
(a)  between  500°  and  600°  the  substance  loses  all  its  water  and  is 
decomposed  into  free  silica  and  alumina,  (6)  polymerisation  of  the 
alumina  occurs  at  800-900°,  and  (c)  the  free  silica  and  alumina  re-com- 


REVIEW  OF  MELLOR  &  HOLDCROFTS  EXPERIMENTS     123 

bine  at  1100-1200°.  This  explanation  of  Mellor  and  Holdcroft's  is 
highly  improbable,  and  is  contradicted  by  their  experimental  results. 
Thus,  the  Table  showing  the  solubility  of  kaolin,  alumina,  and  silica 
which  have  been  heated  to  various  temperatures  (supra)  shows  that 
at  700°  only  0-98  per  cent,  of  the  alumina  presumably  set  free  from  the 
china  clay  is  dissolved,  whilst  20-4  per  cent,  of  the  hydrated  alumina  is 
dissolved  under  similar  conditions.  To  suggest  that  this  low  solu- 
bility is  due  to  the  alumina  being  in  the  nascent  state  is  to  make  the 
whole  experiment  quite  inexplicable,  as  alumina  definitely  known  to  be 
in  this  state  has  a  still  higher  solubility.  In  any  case,  such  a  difference 
in  solubility  as  Mellor  and  Holdcroft  suppose  is  quite  incomprehensible, 
and  their  assumption  that  the  alumina  from  the  clay  is  more  readily 
converted  into  an  insoluble  modification  than  that  existing  when 
hydrated  alumina  is  heated  is  untenable,  as  the  difference  in  solubility 
is  far  too  large.  Moreover,  such  an  assumption  is  unnecessary, 
because,  as  already  explained,  the  hexite-pentite  theory  gives  a  much 
simpler  interpretation  which  is  in  closer  agreement  with  the  facts. 

The  hygroscopicity  of  china  clay,  alumina  and  silica  which  had  been 
heated  to  various  temperatures  has  also  been  determined  by  Mellor 
and  Holdcroft.  The  values  obtained  appear  to  be  in  opposition  to  the 
assumption  that  china  clay  is  dissociated  into  free  alumina  and  free 
silica  at  500-600°. 

The  hygroscopicity  was  determined  by  standing  the  materials  for 
24  hours  at  25°  over  10  per  cent,  sulphuric  acid  and  noting  the  increase 
in  weight ;  this  was  considered  to  be  due  to  the  water  vapour  absorbed. 
The  following  results  were  obtained  by  these  investigators  : 


Temperature. 

Percentage  of  water  absorbed. 

China  Clay. 

Alumina. 

Silica. 

110° 

0.71 

18.35 

600° 

0.33 

9.80 

15.93 

700° 

0.31 

10.33 

15.34 

800° 

0.37 

10.75 

12.85 

900° 

0.34 

9.19 

3.96 

1000° 

0.04 

0.01 

0.00 

The  low  hygroscopicity  of  china  clay  compared  with  that  of  silica 
and  alumina  (600-900°)  is  extremely  puzzling  if  it  is  assumed  that  the 
clay  dissociates  into  free  silica  and  alumina  on  heating.  But  in  the  light 
of  the  H.P.  theory  this  is  readily  understood.  If  china  clay  were  to  dis- 
sociate as  Mellor  and  Holdcroft  assume,  the  product  should  have  a 
much  higher  hygroscopicity  than  it  possesses. 

Another  interesting  investigation  of  Mellor  and  Holdcroft  is  their 
attempt  to  produce  hydrous  china  clay  from  the  dehydrated  (heated) 
material.  Samples  of  china  clay  which  had  been  maintained  for  a  long 


CONSEQUENCES   OF  THE   H.P.  THEORY 

time  at  600-640°  and  still  contained  1-04  per  cent,  of  water  (approxi- 
mately 1  molecule  of  H20)  were  heated  with  water  in  an  autoclave  at 
300°  C.  under  a  pressure  of  200  atmospheres.  The  product,  dried 
over  P205  in  vacuo,  showed  a  loss  on  ignition  of  3-63  per  cent,  (approxi- 
mately 3-5H20),  the  dehydrated  china  clay  thus  absorbing  2-5  per 
cent,  or  2-5  molecules  of  water.  This  behaviour  may  be  predicted 
from  the  Hexite-Pentite  theory. 


The  Melting  Points  of  Clays  and  other  Aluminosilicates 

[Technically,  the  melting  point  of  certain  aluminosilicates  is  of  great  importance. 
Especially  is  this  the  case  with  clays  used  for  the  manufacture  of  furnace  linings  and 
other  refractory  goods  exposed  to  very  high  temperatures.] 

The  melting  point  of  a  substance  has  long  been  recognised  as 
closely  related  to  its  chemical  constitution,  and  C.  Bischof727  was  the 
first  to  establish  the  existence  of  such  a  relationship.  Unfortunately, 
his  conclusions  have  been  found  to  be  incorrect  in  detail,  but  this  does 
not  prejudice  his  position  of  priority  in  this  important  subject. 

[The  fact  should  not  be  overlooked  that  the  determination  of  the  melting  point 
of  clays  is  so  difficult  that  reliable  conclusions  based  upon  it  are  almost  impossible  of 
attainment  in  the  present  state  of  knowledge.  What  is  usually  termed  the  "melting 
point"  is  merely  the  point  at  which  the  influence  of  heat  is  sufficient  to  cause  the 
bending  of  test  pieces  of  an  arbitrarily  chosen  shape  (that  of  Seger  Cones). 

Clays  do  not  appear  to  have  any  definite  melting  point,  but,  on  heating,  the 
amount  of  fused  matter  gradually  increases,  partly  by  the  direct  action  of  the  heat 
and  partly  by  the  chemical  action  of  the  fused  material  on  that  which  remains.  Thus, 
a  clay  which  is  maintained  for  a  sufficiently  long  time  at  a  comparatively  low  tempera- 
ture will  show  a  similar  amount  of  fusion  or  vitrification  to  another  clay  which  has 
been  raised  to  a  higher  temperature  for  a  much  shorter  time.  This  fact  is  extensively 
used  in  the  manufacture  of  stoneware,  paving  bricks  and  other  articles  of  vitrified 
clay,  as  the  loss  of  shape  at  a  given  temperature  on  prolonged  heating  is  far  less 
serious  than  when  a  higher  temperature  is  employed  for  a  much  shorter  time.  In 
the  manufacture  of  glazed  goods,  on  the  contrary,  it  is  found  that  a  little  gloss,  i.e. 
a  more  complete  fusion,  is  obtained  by  means  of  a  more  rapidly  rising  temperature  to 
which  the  goods  are  exposed  for  a  comparatively  short  time.  Hence,  it  is  precisely 
because  clays  behave  as  if  they  were  composed  of  a  refractory  skeleton,  the  pores  of 
which  are,  on  heating,  gradually  filled  with  a  glassy  material,  that  the  manufacture 
of  stoneware,  porcelain,  etc.  becomes  possible.  If  clays  melted  uniformly  the  result 
of  heating  them  in  kilns  would  not  be  the  wares  mentioned,  but  glasses  and  glazes. 

It  would  remove  much  obscurity  and  many  erroneous  conclusions  if  the  term 
"melting  point"  in  the  literature  of  clays  and  clay- working  were  replaced  by  the  term 
softening  point.  The  tests  of  the  so-called  melting  point  of  clays  and  the  temperatures 
associated  with  Seger  Cones  do  not  refer  to  the  true  melting  point  at  all,  but  merely 
indicate  the  effect  of  the  total  forces  acting  on  the  material  and  resulting  in  a  certain 
change  in  shape.  This  change  is  brought  about  by  the  production  in  the  mass  of  a 
certain  amount  of  fused  or  partially  fused  material  and  is  the  resultant  of  several 
forces,  the  individual  influence  of  which  it  is  extremely  difficult  to  calculate. 

The  generally  accepted  view  of  the  phenomena  observed  in  the  melting  point  of 
clays  is  that  they  point  to  the  fusion  of  the  least  refractory  materials  in  the  clay 
occurring  first,  this  being  followed  by  the  gradual  fusion  of  the  remainder  by  the 
fused  portion.  This  view  is  confirmed  by  the  fact  that  clays  do  not  appear  to  have  a 
definite  melting  point  like  crystalline  compounds,  but  a  "range  of  fusion"  such  as  is 
found  on  heating  heterogeneous  mixtures. 

In  view  of  the  H.P.  theory,  it  is  not  impossible  that  the  low  conductivity  of  clay 
for  heat  may  lead  to  erroneous  conclusions  respecting  the  fusing  points  of  articles 
made  of  clay  by  preventing  the  heat  reacting  on  the  interior  of  the  mass.  The  results 
of  prolonged  heating  at  lower  temperatures  appear  to  confirm  this  view.  To  decide 
whether  a  clay  has  a  sharp  melting  point  (like  a  single  chemical  compound)  or  a 


MELTING   POINTS   OF   CLAYS,   ETC.  125 

"melting  range"  (like  a  heterogeneous  mixture)  it  would  be  necessary  to  keep  it  for 
a  sufficiently  long  time  at  the  lowest  temperature  at  which  any  fusion  appears  to 
occur.  The  time  required  is  so  great  that  the  cost  of  such  tests  becomes  prohibitive, 
but  until  they  have  been  made  it  is  not  logical  to  assume  that  the  apparent  behaviour 
of  clays  is  necessarily  opposed  to  their  being  definite  chemical  compounds  and  not 
mixtures.  It  is,  moreover,  not  impossible  that  the  progressive  decomposition  of  the 
molecules  containing  substituted  elements  may  make  what  are  really  true  compounds 
behave  as  heterogeneous  mixtures,  though  the  former  suggestion  appears  to  afford  a 
more  probable  explanation.] 

That  a  close  relationship  does  exist  between  the  melting  point  and 
chemical  constitution  of  a  compound  cannot  be  denied,  and  this  being 
the  case,  the  following  statements  are  direct  consequences  of  the  H.P. 
theory : — 

1.  Clays  are  usually  kaolinic  acids  which  have  undergone  a  partial 
polymerisation.  In  the  theoretically  possible  compound  : 


I      I 


Si  I  Al  I  Al  I  Si 

*/V\ 

II     I     I 

18  H20  •  18  A1203  •  36  Si02, 

one  or  more  hydrogen  atoms  may  be  replaced  by  K,  Na,  Ca,  Mg,  Fe, 
etc. ;  one  or  more  aluminium  atoms  may  be  replaced  by  Fe,  Mn,  Cr,  Co, 
etc.  ;  one  or  more  silicon  atoms  may  be  replaced  by  Ti,  Zr,  etc.  By 
such  replacements  compounds  would  be  produced  containing  very 
small  percentages  of  certain  elements  which  would,  nevertheless,  have  a 
marked  influence  on  the  melting  point.  It  is  obvious  that  this  influence 
must  be  different  with  different  elements.  Not  only  must  bases  have  a 
different  effect  on  the  melting  point  from  that  exerted  by  acids,  but 
the  various  bases  and  acids  will  vary  in  their  individual  influence. 
Hence,  the  melting  point  of  the  material  will  be  affected  according  as 
K,  Na,  Ba,  or  Ca,  etc.  replaces  one  or  more  hydrogen  atoms,  and 
whether  a  portion  of  the  aluminium  is  replaced  by  Fe  or  Cr  or  Mn,  etc., 
or  whether  Ti  or  Zr  is  substituted  for  part  of  the  silicon. 

Other  variations  in  the  melting  point  will  occur  according  as  a 
portion  of  the  hydrogen,  aluminium  or  silicon  is  replaced  by  analogous 
substances. 

In  all  these  cases  the  melting  point  is  a  periodic  function  of  the 
atomic  weight  of  the  substituting  element,  i.e.  there  must  be  a  definite 
relationship  between  the  change  in  the  melting  point  and  the  atomic 


126  CONSEQUENCES   OF  THE   H.P.   THEORY 

weight  of  the  replacing  element.  As  the  atomic  weight  increases,  the 
melting  point  of  the  clay  may  rise  or  fall. 

2.  Clays  and  aluminosilicates   have  varying  A1203  :  SiO2  ratios. 
With  any  variation  in  the  proportion  of  alumina  or  silica  the  melting 
point  of  the  clay  must  also  rise  or  fall. 

3.  The  melting  points  of  isomeric  aluminosilicic  acids  and  of  the 
corresponding  salts  must  differ  from  each  other. 

(See  "  Basis  and  Ring  Isomerism,"  p.  63.) 

The  H.-P.  Theory  and  the  Facts 

The  available  experimental  evidence  is  not  sufficient  to  prove 
completely  the  foregoing  consequences  of  the  H.P.  theory  regarding  the 
relationship  of  the  melting  point  and  the  chemical  constitution  of 
clays.  Such  facts  as  are  known,  however,  are  confirmatory  of  the 
theory. 

Consequence  1  (p.  125) 

It  follows  from  the  theory  that  the  melting  point  of  a  clay  must 
depend  on  the  nature  of  the  elements  which  replace  some  of  the  H, 
Si  or  Al  in  the  theoretically  pure  kaolinic  acid  or  clay.  Opposed  to  this 
theory  is  the  law  of  Bischof  and  Richter726  which  states  that  "  equiva- 
lent amounts  of  fluxes  have  an  equal  influence  on  the  melting  point  of 
any  clay  in  which  they  occur." 

[In  order  to  obtain  a  numerical  expression  of  this  law,  Bischof  re-calculated  the 
analyses  of  the  clays  he  examined  so  as  to  show  their  molecular  proportions,  and 
arranged  these  as  a  formula  of  the  type 

O  •  aA!2O3  •  6SiO2, 

in  which  the  amount  of  base  is  constant,  the  two  variables  being  the  silica  and  alumina. 
Considering  these  variables  alone,  he  suggested  that  the  refractoriness  of  a  clay  might 
be  represented  by  a  coefficient  or  quotient  (FQ).  According  to  Bischof : 

a2 
Fire  resistance  Quotient  (Bischof)  FQg  =~r*] 

According  to  this  law,  it  follows  that  equivalent  amounts  of  potash, 
soda,  ferric  oxide,  etc.  should  have  an  equal  influence  on  the 
melting  point  of  clays  containing  them.  The  following  compositions 
of  clays  may  be  taken  as  an  illustration  : 

0.5  K20-  9.5  H20    •     6A1203  •  12  Si02, 

0.5  Na2O  •  9.5  H80    •     6  A12O3  •  12  Si02, 

0.25  K20  •  0.25  Na20  •  9.5  H20    •     6  A1203  •  12  SiO2, 

10  H20  •  5.5  A1203  •  0.5  Fe203  •  12  Si02, 

10  H20  •  5.5  A1203  •  0.5  Mn203  •  12  Si02. 

These  contain  the  same  amount  of  fluxes,  viz.  0-5  molecules,  and 
should  all  have  the  same  melting  point.  Actual  determinations  of  the 
melting  points  of  these  clays  show  that  this  is  not  the  case. 


RELATION  BETWEEN  MELTING  POINT  &  COMPOSITION    127 


In  direct  opposition  to  Bischof  and  Richter's  law  are  the  extensive 
studies  of  Jochum728  on  a  series  of  fireclays  in  connection  with  Seger 
Cones.  The  data  obtained  by  Jochum  are  summarised  in  the  following 
Table  : 


No. 

SiOa 

Al,03 

Fea03 

CaO 

MgO 

Kao 

Na,0 

Total 
Fluxes 

Kefractorineas 
in  Seger  Clones 

1. 

53.32 

44.15 

0.56 

0.28 

0.23 

0.51 

1.58 

36 

2. 

52.24 

43.43 

0.87 

— 

0.32 

0.35 

— 

1.54 

35 

3. 

52.50 

45.22 

0.81 



0.54 

0.50 



1.85 

35 

4. 

52.74 

45.81 

1.00 

0.15 

0.05 

0.54 



1.74 

36 

5. 

52.50 

46.25 

0.35 

0.47 

0.13 

0.32 

— 

1.27 

36 

6. 

52.33 

45.81 

1.30 





1.43 

— 

2.73 

35 

7. 

53.11 

44.63 

2.34 

0.86 

0.65 

0.22 

— 

4.07 

35-36 

8. 

52.74 

46.00 

1.07 



0.23 

0.24 

— 

1.54 

35 

TiO2 

9. 

53.35 

44.13 

0.89 

0.28 

— 

1.34 

1.11 

3.62 

35 

10. 

53.35 

43.35 

0.83 

0.24 

— 

1.43 

— 

2.50 

35 

11. 

51.45 

45.23 

0.55 

0.30 

0.41 

1.78 



3.03 

35 

12. 

51.57 

45.70 

1.31 

0.86 



0.77 



2.94 

35 

13. 

51.57 

45.90 

1.13 

0.24 

0.09 

0.60 



2.06 

35 

14. 

51.90 

46.10 

1.14 

0.24 

0.09 

0.60 

— 

2.07 

35-36 

15. 

51.43 

45.57 

1.31 

0.89 



0.77 

— 

2.97 

35 

16. 

55.00 

40.60 

2.86 

1.30  Di 

ff. 

— 

4.16 

35 

17. 

57.00 

37.00 

3.66 

0.57 

— 

1.77 

— 

6.00 

35 

18. 

58.19 

39.37 

0.85 

0.09 

0.41 

1.14 

— 

2.49 

34 

19. 

52.34 

40.11 

2.54 

0.25 

0.91 

3.87 

— 

7.57 

33 

20. 

52.92 

39.16 

2.57 

0.18 

1.24 

3.55 

— 

7.54 

30 

21. 

52.48 

39.16 

2.55 

0.18 

1.23 

3.52 



7.48 

32 

22. 

52.90 

38.40 

4.80 

2.40 

0.80 

1.00 

— 

9.00 

32 

A  glance  at  this  Table  will  show  the  invalidity  of  Bischof  and 
Richter's  law.  This  is  particularly  noticeable  with  respect  to  clays  Nos. 
6,  7,  and  8.  The  total  percentage  of  fluxes  in  No.  6  clay  is  2-73,  in 
No.  7  clay  4-07  and  in  No.  8  clay  1-54,  but  the  refractoriness  of  all  three 
clays  is  the  same  (cone  35).  Indeed,  the  clay  with  the  lowest  pro- 
portion of  fluxes  (No.  7)  has,  if  anything,  a  higher  degree  of  refractori- 
ness than  the  other  two.  The  figures  in  connection  with  clays  No.  17 
and  18  are  even  more  striking.  Clay  No.  17  contains  6-00  of  fluxes 
whilst  No.  18  contains  only  2-49,  yet  the  refractoriness  of  No.  17  is  a 
Seger  cone  higher  than  No.  18,  i.e.  cone  35  as  compared  with  cone  34, 
whereas,  according  to  the  Bischof -Richter  law,  No.  17  should  be  con- 
siderably more  fusible  than  No.  18.  In  the  case  of  clays  No.  19  and  21, 
the  composition  is  practically  identical,  but  the  refractoriness  is 
different. 

[Seger730  has  pointed  out  that  the  Bischof-Richter  law  is  only  applicable  to  clays 
containing  a  very  small  proportion  of  basic  oxides,  i.e.  to  the  most  highly  refractory 
clays,  and  that  it  is  quite  useless  for  second-grade  fireclays  and  clays  used  for  building 
purposes. 

Richter730  found  that  the  form  in  which  the  silica  is  present  in  a  clay,  i.e.  whether 
combined  or  in  the  free  state,  has  a  profound  influence  on  the  melting  point.  Hence, 
as  Seger  has  pointed  out,  the  resistance  of  clay  to  heat  does  not  depend  on  the  com- 
position of  the  material  as  a  whole,  but  on  the  compounds  present  in  it  and  on  their 
state  of  aggregation.  This  fact  has  been  repeatedly  confirmed  and  is  well  known  to  all 


128 


CONSEQUENCES   OF  THE   H.P.   THEORY 


manufacturers  of  refractory  goods.  Indeed,  the  remarkable  variations  in  fireclay 
deposits  are  a  daily  source  of  anxiety  to  those  using  them.  For  this  reason,  and  because 
he  regarded  the  variety  of  minerals  present  in  most  clays  as  rendering  abortive  all 
consideration  of  the  melting  point  of  any  clay  as  a  whole,  Seger730  insisted  that  it  is 
first  necessary  to  free  the  clay  as  far  as  possible  from  sand,  silt,  and  other  impurities 
by  washing,  and  then  to  study  the  melting  point  of  the  purer  product  thus  obtained. 
He  therefore  applied  Bischof's  Quotient  to  that  portion  of  the  clay  which  is  sufficiently 
fine  to  be  washed  out  by  a  current  of  water  flowing  at  the  rate  of  0. 1 8  mm.  per  second 
(i.e.  on  the  nearest  approach  to  "  pure  clay  "  obtainable  on  mechanical  elutriation  of 
a  commercial  clay  and  termed  by  him  "  clay  substance,"  but  more  accurately  clayite 
in  the  case  of  china  clay  by  J.  W.  Mellor708,  and  pelinite  in  the  case  of  plastic  clays  by 
A.  B.  Searle732).  With  this  purified  material  Seger  obtained  results  which  agreed  much 
better  with  the  actual  fusion  tests.  As,  however,  serious  discrepancies  still  existed — 
even  among  the  higher-grade  clays — Seger  eventually  suggested  the  following  formula 
applied  to  the  clayite  or  pelinite  above  mentioned,  and  not  to  the  material  as  a  whole  : 

Fire-resistance  Quotient  (Seger)  FQg  =  (a+b)  5. 

This  formula,  though  applicable  to  a  larger  number  of  clays  than  Bischof's,  is, 
like  the  latter,  extremely  limited  in  its  application  and  is  far  from  reliable,  and  Seger 


•30 
•25 
-20 
-ft 
-ID 
-05 


\ 


\ 


\ 


» 


\ 


* 


s.c, 


2         25        3          3-S 
FIG.  1. — Lud wig's  Chart 


4-5        5       55      6 


himself  found  several  fireclays  and  kaolins  in  regard  to  which  it  proved  impossible  to 
obtain  an  agreement  between  his  formula  and  the  results  of  actual  fusion  tests.  That  Seger 
recognised  this  is  clearly  shown  in  the  following  statements  in  his  "  Collected  Papers  "  : 
"  Both  Bischof's  and  my  coefficients  only  give  approximate  figures,  as  the  fusion  of 
clays  involves  several  important  physical  factors  which  must  inevitably  be  omitted 
from  any  method  of  calculation."  "It  is  unwise  to  attach  much  importance  to  any 
coefficient,  because  it  cannot  include  the  variations  in  the  size  of  the  grains  of  clay, 
this  factor  being  quite  as  important  as  the  composition  of  the  material.  Thus,  silica 
in  an  extremely  finely  divided  state  acts  energetically  as  a  flux,  but  coarser  silica  in- 
creases the  heat  resistance  of  some  clays  to  which  it  is  added  !  "  Seger  also  laid  great 
stress  on  the  irregularity  of  composition  observed  in  clays,  and  declared  them  to  be 
"  not  homogeneous,  but  merely  mixtures  of  various  minerals  of  which  the  largest 
proportion  is  *  clay  substance.'  "  "  Hence,  any  figure  which  it  is  claimed  represents  the 
melting  point  based  on  the  composition  of  the  material  can  only  be  rough  approxima- 
tions." 

When  Seger's  quotient  is  applied  to  the  analyses  shown  in  the  Table  on  page  127, 
the  results  obtained  are  so  conflicting  that  it  is  impossible  to  trace  any  direct  con- 


RELATION  BETWEEN  MELTING  POINT  &  COMPOSITION    129 

nection  between  Seger's  quotient  and  the  Seger  cone  numbers  in  the  last  column  of 
the  Table.  It  is,  however,  only  fair  to  observe  that  the  temperatures  indicated  by 
these  Seger  cones  are  not  the  true  melting  points  of  the  clays,  but  only  the  "  softening 
points,"  and  Bischof  has  shown  there  is  no  simple  law  connecting  the  temperature  at 
which  Seger  cones  bend  with  that  at  which  they  melt. 

A  method  of  calculation  similar  to  those  of  Bischof  and  Seger,  but  differing  in 
the  manner  of  its  representation,  is  that  of  T.  Ludwig706,  who  assumed  that  the  fluxes 
in  a  clay  are  in  the  form  of  a  solid  solution  with  the  clay  as  a  solvent,  and  arranged 
the  composition  of  a  clay  as  a  formula  with  alumina  as  unity  thus  : 

x  RO     A12O3    y  SiO2, 

plotting  x  as  ordinates  and  y  as  abscissae.  Ludwig  obtained  a  chart  (Fig.  1)  in  which 
the  diagonal  lines  represent  the  limits  of  the  Seger  cones  marked  thereon,  so  that  the 
"  melting  point  "  of  a  clay  is  represented  in  terms  of  these  cones.  This  chart  is  in 
close  agreement  with  the  experimental  observations  of  many  fireclays  and  kaolins, 
but  is  entirely  unreliable  for  clays  in  which  the  total  fluxing  oxides  exceed  6  per  cent. 
Ludwig  attributed  its  failure  to  the  heterogeneous  nature  of  clays  and  to  the  irregular 
distribution  of  the  fluxes  in  them. 

The  relationship  between  the  composition  of  clays  and  their  melting  point  has 
also  been  investigated  by  H.  Seger730,  who  studied  the  melting  point  of  mixtures  of 
silica  and  alumina  and  of  silica  and  kaolin  to  which  sufficient  felspar  was  added  to 
keep  the  alkali-content  of  the  various  mixtures  constant. 

Seger  found  that  mixtures  of  free  silica  and  alumina  behave  in  a  manner  similar 
to  mixtures  of  kaolin  and  pure  quartz-sand,  so  far  as  the  melting  points  are  concerned. 
In  both  cases  the  larger  the  proportion  of  silica  the  lower  the  melting  point,  until  a 
material  is  obtained  with  a  molecular  ratio  of  1  A12O3  :  17  SiO2,  after  which  the 
addition  of  more  silica  increases  the  melting  point  until  practically  pure  silica  is 
obtained.  These  results  are  summarised  in  the  curve  shown  in  Fig.  2  (see  also 
p.  132). 

That  some  definite  relationship  does  exist  between  the  composition  and  the 
softening  point  of  clays  is  shown  by  the  existence  of  a  regular  series  of  Seger  cones. 
These  are  composed  of  mixtures  of  pure  kaolin  with  marble,  felspar,  and  quartz  in 
atomic  proportions,  the  whole  being  reduced  to  an  exceedingly  fine  powder.  Not- 
withstanding the  fact  that  the  purest  possible  materials  are  used  in  the  manufacture 
of  these  cones,  no  definite  general  formula  has  been  found  for  connecting  the  fusing 
point  of  these  cones  with  their  composition.  Seger  laid  special  emphasis  on  the  un- 
desirability  of  attempting  to  correlate  the  Seger  cones  with  definite  temperatures. 
"  I  permit  the  preparation  of  a  scale  of  comparison  between  my  cones  and  definite 
temperatures,"  he  wrote,  "  with  the  greatest  unwillingness,  more  especially  as  I  have 
found  no  means  of  comparison  for  the  highest  cones."  Seger's  caution  and  modesty 
are  well  known,  so  that  it  is  interesting  to  note  that  later  investigations  have  proved 
that,  with  trifling  exceptions,  all  the  cones  above  No.  10  correspond  very  closely  to 
definite  temperatures,  provided  that  the  rate  and  other  conditions  of  heating  are 
favourable  and  constant,  but  that  slight  variations  in  the  condition  of  heating  cause 
serious  discrepancies  in  the  behaviour  of  the  cones.  It  should,  however,  be  noted 
that  Seger's  cones  do  not  show  the  melting  points  of  the  mixtures  composing  them, 
but  only  the  resultant  of  the  various  forces  which  cause  them  to  bend  to  a  definite 
extent.  Whether  there  is  any  relationship  capable  of  simpler  expression  numerically 
between  the  bending  temperatures  of  Seger  cones  and  their  true  melting  points  remains 
to  be  proved.  Meanwhile,  in  view  of  the  misuse  of  terms  in  the  literature  of  the  subject, 
too  much  emphasis  cannot  be  laid  on  the  fact  that  Seger  cones  merely  indicate  the 
softening  points  of  the  materials  of  which  they  are  made.  These  softening  points, 
together  with  the  molecular  composition  of  the  cones,  are  shown  in  the  Table 
on  the  next  page. 


130 


CONSEQUENCES  OF  THE   H.P.  THEORY 

SEGER  CONES  AND  TEMPERATURES 


Estimated 
Temperature  °  C. 

Cone  No. 

Molecular  Composition 

K,0 

CaO 

Al,0, 

SiO, 

1320 

11 

.25 

.58 

1 

10 

1350 

12 

.21 

.50 

1 

10 

1380 

13 

.19 

.53 

1 

10 

1410 

14 

.17 

.39 

1 

10 

1435 

15 

.14 

.33 

1 

10 

1460 

16 

.13 

.29 

1 

10 

1480 

17 

.11 

.26 

1 

10 

1500 

18 

.10 

.23 

10 

1520 

19 

.09 

.20 

10 

1530 

20 

.08 

.18 

10 

p 

21 

.07 

.15 

10 

22 

.06 

.14 

10 

*- 

23 

.06 

.13 

10 

24 

.05 

.12 

10 

25 

.04 

.11 

10 

1580 

26 

.04 

.10 

10 

1610 

27 

.02 

.03 

10 

1630 

28 

— 

— 

10 

* 

28* 

— 

— 

9 

1650 

29" 

— 

— 

8 

* 

29* 

— 

— 

7 

1670 

30" 



— 

6 

1690 

31 



— 

5 

1710 

32f 

— 

— 

4 

1730 

33 

— 

— 

3 

1750 

34 



— 

2.5 

1770 

35 



— 

2 

1920 

40 

— 

— 

— 

*  These  cones  are  not  manufactured,  as  their  Estimated  Temperatures  lie  too  close 
to  neighbouring  cones,  and  are  somewhat  irregular, 
t  Pure  silica  behaves  like  cone  32. 

It  will  be  observed  that  there  is  a  fairly  regular  difference  in  temperature  between 
consecutive  cones,  but  this  is  not  sufficiently  constant  for  any  simple  law  to  be  found 
from  a  graph  of  the  cone  numbers  and  temperatures. 

Simonis706  has  studied  mixtures  of  kaolin,  quartz,  and  felspar  in  connection  with 
Seger  cones  and  found  that  the  felspar  acts  as  a  constant  and  neutral  flux.  He  also 
concluded  that  the  softening  point  of  such  a  mixture  might  be  represented  numerically 
by  a  "  refractory  index,"  using  the  symbols  k  for  the  percentage  of  kaolin,  s  for  that 

of  quartz,  and  /  for  that  of  felspar.    According  to  Simonis,  if  k  is  greater  than  f  the 

"  refractory  index  "  will  be  R  =  |  —  /  +  60.     For  bodies  high  in  silica,  in  which 

«J 

2g 
o  is  greater  than  Tc,  the  "  refractory  index  "  is  IT  —  k  —  f  +  60.     The  value  of  this 

"  refractory  index  "  in  terms  of  Seger  cones  is  given  in  the  accompanying  Table  : — 


Refractory  index    .  . 

17.5 

22.6 

28 

33.7 

39.2 

44.6 

50 

57.6 

14 

15 

16 

17 

18 

19 

20 

26 

Refractory  index   .  . 

65 

72 

80 

89 

102 

114 

127 

141 

Seger  cone  

27 

28 

29 

30 

31 

32 

33 

34 

RELATION  BETWEEN  MELTING  POINT  &  COMPOSITION    131 

It  will  be  observed  that  there  is  no  simple  relationship  between  Simonis'  Refractive 
Index  and  the  corresponding  Seger  Cones. 

In  short,  the  Bischof-Richter  law,  together  with  the  various  modi- 
fications of  it  and  the  other  attempts  to  correlate  the  melting  points  of 
clays  with  their  chemical  constitution  here  noticed,  which  are  not  in 
accordance  with  the  H.  P.  theory,  is  shown  by  the  above  evidence  to  be 
erroneous.  Further  investigations  must  show  that,  in  accordance  with 
the  H.P.  theory,  the  true  melting  point  of  a  clay  (not  the  "  softening 
point  ")  is  a  periodic  function  of  the  atomic  weight  of  the  replacing 
elements. 

[That  this  relationship  has  not  been  f  ound  is,  in  part,  due  to  the  difficulties  experi- 
enced in  melting  the  purer  and  therefore  the  most  refractory  clays,  and  also  to  the 
very  widespread  belief  that  clays  are  heterogeneous  mixtures  and  not  true  chemical 
compounds.  The  general  evidence  in  favour  of  the  H.P.  theory  is,  however,  so  strong 
as  to  make  this  consequence  of  it  highly  probable,  even  though  the  experimental 
evidence  at  present  available  in  respect  of  melting  points  is  of  little  or  no  assistance. 
In  due  time  the  various  germs  of  truth  in  Bischof's  and  other  theories  will  emerge 
from  the  obscurity  in  which  they  have  so  long  lain,  in  consequence  of  the  non-existence 
of  a  correct  theory  as  to  the  constitution  of  clays  and  allied  substances.] 

It  is  highly  probable  that  the  melting  point  will  be  lowered  by  the 
substitution  of  elements  of  higher  atomic  weights.  Such  an  effect  has 
been  observed  by  G.  Jantsch729  in  other  complexes  with  the  general 
formula  : 

3Mo-X203-6N205-24H20, 

where  Mo  =  MgO  •  MnO  •  NiO  •  CeO  •  ZnO,  and 
X203  =  La203  •  Ce2O3  -  Pr2O3  -  Nd203  -  Sm203  •  Gd203. 

This  is  shown  in  the  following  Table  : 


Mg 

Mn 

Ni 

Ce 

Zn 

La 

113.5° 

87.2° 

110.5° 

101.8° 

98.0° 

Ce 

111.5° 

83.7° 

108.5° 

98.5° 

92.8° 

Pr 

111.2° 

81.0° 

108.0° 

97.0° 

91.5° 

Nd 

109.0° 

77.0° 

105.6° 

95.5° 

88.5° 

Sm 

96.2° 

70.2° 

92.2° 

83.2° 

76.5° 

Gd 

77.5° 



72.5° 

63.2° 

56.5° 

The  divalent  manganese  appears  to  behave  in  an  exceptional 
manner  which  cannot,  at  present,  be  explained. 

Consequence  2  (see  p.  126) 

The  melting  point  of  silicates  containing  no  alumina  increases  with 
the  silica-content.  Thus,  bisilicates  fuse  at  a  higher  temperature  than 
monosilicates,  and  trisilicates  are  more  difficult  to  fuse  than  bisilicates. 

In  most  cases,  the  physical  properties  of  complex  substances  differ 
from  those  of  their  constituents.  This  is  also  the  case  with  alumino- 
silicates  in  which,  according  to  the  researches  of  C.  Bischof,  a  lower 
fusing  point  accompanies  a  higher  silica-content,  the  aluminosilicates 
which  are  rich  in  silica  being  more  fusible  than  those  relatively  poor  in 
silica. 


132 


CONSEQUENCES  OF  THE   H.P.   THEORY 


A  glance  at  Fig.  2,  which  shows  the  results  obtained  by  Seger730 
on  mixtures  of  pure  silica  and  alumina  (see  p.  129)  shows  : — 

1.  An  increase  in  the  proportion  of  silica  is  accompanied  by  an 
increased  fusibility. 

2.  The  melting  point,  or  more  strictly  the  softening  point,  di- 
minishes with  an  increase  in  the  proportion  of  silica  until  the  mixture 
with  a  ratio  A1203 :  SiO2  =  l  :  15  is  reached,  after  which  there  is  a 
change  in  the  direction  of  the  curve  until  a  ratio  1  :  17  is  reached,  after 
which  an  increase  in  the  proportion  of  silica  is  accompanied  by  an 
increase  in  the  melting  point. 

°u  red/2  Os 


0    I     23456    7    8    9    10    II  12   13  /4  15  IB  17  IB   13  20  21  22  23  24  25 

Mols.SiOz. 

FIG.  2. — Relation  of  Softening  Point  to  Composition  (Seger) 

The  flattening  in  the  curve  indicates  the  formation  of  a  compound, 
and  as  glasses  are  known  with  a  ratio  of  A12O3 :  SiO2  =  2  :  36,  the  curve 
appears  to  indicate  the  existence  of  a  secondary  type  of  such  a  glass. 
The  compound  A12O3,  17  Si02  would  then  have  a  high  molecular  weight 
and  the  following  structural  formula  : — 


Si  |  Si  |  Si  | 
\/       \/ 

A12        A12 

A A 

|  Si  |  Si  |  Si 
\/\/\/ 


Consequence  3  (see  p.  126) 

No  experimental  evidence  is  available  for  proving  the  correctness  or 
otherwise  of  this  consequence  of  the  H.P.  theory,  but  further  investiga- 


THE   CAUSE   OF   PLASTICITY  133 

tions  of  clays  and  aluminosilicates  will,  in  all  probability,  lead  to  the 
definite  confirmation  of  this  theory. 


In  connection  with  the  foregoing  observations  the  behaviour  of  the 
so-called  mineralisers1™  may  be  mentioned.  The  ones  most  generally 
used  are  the  chlorides  of  calcium,  magnesium,  manganese,  aluminium, 
and  silicon,  the  fluorides  of  calcium,  sodium,  potassium,  magnesium 
and  silicon,  the  tungstates  of  potassium  and  lithium,  the  borates  of  mag- 
nesium, calcium  and  sodium,  the  phosphates  of  potassium,  magnesium, 
etc.  These  mineralisers  appear,  in  many  cases,  to  form  sodalitic  com- 
pounds with  silicates  (see  Socialites  p.  59)  and,  on  adding  a  mineraliser 
to  a  compound  or  mixture,  the  melting  point  of  the  substance  is  con- 
siderably reduced. 

Mineralisers  play  an  important  part  in  the  synthesis  of  various 
minerals  and  without  them  some  minerals  cannot  be  produced. 

The  Cause  of  Plasticity  in  Clay 

Before  concluding  this  chapter,  a  few  words  may  be  added  on  the 
plasticity  of  clay. 

The  authors  agree  with  Seger221  in  terming  those  substances  plastic 
which  possess  the  power  of  absorbing  and  retaining  fluids  in  their  pores 
in  such  a  manner  that  the  mass  may  be  given  any  desired  shape  by 
kneading  or  pressure,  this  shape  being  retained  after  the  pressure  has 
been  removed.  It  is  a  further  condition  that  if  the  fluid  is  removed, 
the  substance  shall  retain  its  shape  unchanged. 

A  number  of  theories221*  have  been  formulated  to  explain  the 
causes  of  the  plasticity  of  clays.*  The  authors  of  the  present  volume 
consider  those  theories  are  the  most  probable  which  assign  the  chief 
cause  of  plasticity  to  the  "  water  of  constitution  "  in  clays. 

From  this  it  follows  that  : 

A.  The  more  OH-groups  a  clay  contains  in  the  form  of  "  water  of 
constitution,"  the  more  plastic  must  it  be. 

B.  By  separation  of  the  OH-groups  on  an  increase  in  temperature 
of  the  clay,  or  by  the  replacement  of  hydrogen  by  a  base,  the  plasticity 
must  be  reduced  or  completely  destroyed. 

These  consequences  of  the  theory  are  fully  confirmed  by  facts. 

Thus,  Seger221  found  that  if  a  cream  or  slip  made  of  clay  and  water 
is  allowed  to  settle  and  the  clear  water  decanted,  the  pasty  sediment  will 
be  so  stiff  that  it  can  bear  the  weight  of  a  glass  rod  without  the  latter 
sinking  into  it.  If,  however,  to  the  water  used  for  making  the  slip 
a  few  drops  of  caustic  soda,  sodium  carbonate  solution  or  water-glass 
are  added,  so  that  the  water  is  rendered  feebly  alkaline,  a  remarkable 
change  occurs.  The  slip  becomes  considerably  thinner  and  more  fluid, 

*  The  chief  of  these  are  summarised  in  "  British  Clays,  Shales,  and  Sands."  706 


134  CONSEQUENCES   OF  THE   H.P.   THEORY 

part  of  the  material  settles  immediately  to  the  bottom  as  a  solid 
substance  and  the  supernatant  liquid  requires  a  very  long  time  before 
it  becomes  clear.  If,  now,  a  few  drops  of  acid  are  added  to  the  mass, 
it  becomes  so  stiff  that  the  vessel  in  which  it  is  contained  may  be 
inverted  without  spilling  the  contents.  On  drying  to  a  definite  volume, 
the  acidulated  mass  will  be  found  to  be  much  more  plastic  than  the 
original  clay  and  the  alkaline  mass  will  have  lost  almost  all  its  plas- 
ticity. It  is  highly  probable  that  in  Seger's  experiment,  the  prolonged 
action  of  water  or  acids  on  the  clay  had  effected  a  partial  separation  of 
the  alkalies  it  contained,  whereby  an  increase  in  plasticity  resulted, 
due  to  the  cause  indicated  in  Conclusion  A  above2213. 

By  the  action  of  alkali,  a  partial  substitution  of  H  by  the  alkali  may 
also  occur  and,  as  indicated  in  Conclusion  B,  this  is  the  reason  the 
plasticity  is  reduced. 

E.  v.  Sommaruga222  has  shown,  by  analysis,  that  aluminosilicates  of 
the  alkalies  and  alkaline  earths  lose  part  of  their  base  on  washing. 

In  agreement  with  Conclusion  B,  there  is  the  further  fact  that  clays 
lose  their  plasticity  at  high  temperatures,  at  which  the  water  of  con- 
stitution is  also  driven  off. 

The  fact  that  some  hydrous-aluminosilicates,  such  as  the  zeolites, 
are  non-plastic  is  not  in  opposition  to  the  above  theory  as  to  the 
cause  of  plasticity,  as  the  introduction  of  a  definite  proportion  of  base 
so  as  to  form  a  salt — and  zeolites  are  true  salts — completely  destroys 
the  plasticity. 

[The  term  plasticity,  as  ordinarily  used,  includes  so  many  other  properties  that 
the  interpretation  of  experimental  results  is  extremely  difficult.  Moreover,  no  generally 
accepted  method  of  measuring  plasticity  has  yet  been  devised,  all  those  now  in  use 
being  open  to  several  objections,  the  chief  of  which  is  that  they  measure  some  property 
closely  allied  to  plasticity — such  as  tensile  strength,  adhesion,  viscosity,  binding  power, 
etc.,  but  not  the  plasticity  itself. 

Again,  Drs.  W.  and  D.  Asch  make  no  mention  of  the  close  connection  between 
the  colloidal  material  present  and  the  plasticity  of  clays,  nor  do  they  explain  how  it 
is  that  quartz,  calcium  fluoride  and  a  number  of  other  substances  of  widely  different 
constitution  and  composition  have  been  found  by  Flett,  Atterberg  and  others  to  be 
plastic  when  in  a  sufficiently  finely  divided  state. 

If  it  is  really  a  fact  that  extremely  finely  divided  silica  which  is  free  from  con- 
stitutional water  can  become  truly  plastic,  the  hexite-pentite  theory  will  require 
modification.  In  the  present  state  of  knowledge  it  is,  however,  extremely  difficult  to 
decide  whether  the  substances  just  mentioned  do  become  truly  plastic  or  whether 
they  merely  become  more  cohesive. 

Several  investigations,  including  those  by  Rieke707,  have  shown  that  the  loss  of 
plasticity  when  a  clay  is  heated  is  not  proportional  to  the  loss  of  "  water  of  constitu- 
tion." A  certain  amount  of  plasticity  remains,  even  when  all  the  water  has  been  re- 
moved from  the  clay,  provided  that  the  removal  has  been  effected  at  a  low  tempera- 
ture. For  this  reason  Rieke  and  others  have  concluded  that  the  loss  of  plasticity 
on  heating  is  due  to  the  physical  rather  than  to  the  chemical  nature  of  the  clay.  An 
equally  correct  conclusion  and  one  which  is,  moreover,  in  conformity  with  the  hexite- 
pentite  theory,  is  that  the  loss  of  "  water  of  constitution  "  is  accompanied  by  poly- 
merisation phenomena  which  materially  reduces  the  plasticity  and  necessarily  involves 
a  lack  of  proportionality  between  the  loss  of  water  and  of  plasticity  when  the  clay  is 
heated,  especially  as,  under  such  conditions,  the  plasticity  is  lost  at  a  greater  rate 
than  the  "water  of  constitution." 

The  reader  interested  in  this  subject  will  find  further  details  in  the  translator's 
"  British  Clays,  Shales,  and  Sands,"  in  which  the  conclusion  is  reached  that  the  plasticity 
is  partly  due  to  the  extreme  smallness  of  the  clay  particles,  partly  to  the  shape,  texture, 
and  physical  nature  of  these  particles,  and  only  slightly  to  their  chemical  composition. 


THE   COLOUR   OF  BURNED  CLAY  135 

Considering  the  great  stability  of  the  clay  molecule,  it  certainly  appears  to  be  quite 
as  likely  that  the  action  of  a  few  drops  of  acid  or  alkali  on  a  considerable  weight  of  clay 
may  be  due  to  the  colloidal  material  in  clay  as  to  any  change  in  the  chemical  com- 
position of  the  clay  molecule  of  the  nature  suggested  above.  Moreover,  it  is  difficult 
to  understand  why  china  clays  and  kaolins  should  be  so  slightly  plastic  compared  to 
ball  clays  yielding  such  remarkably  similar  results  on  analysis,  unless  plasticity  origin- 
ates largely  in  the  physical,  rather  than  in  the  chemical  nature  of  clay.  This  may, 
of  course,  be  due  to  somewhat  different  chemical  structure  (isomerism  or  polymerism) 
and  the  hexite-pentite  theory  is  a  priori  in  favour  of  such  an  explanation  as  accounting 
for  the  physical  differences. 

The  whole  subject  of  plasticity  is,  however,  so  complex,  that  no  definite  theory  as 
to  its  cause  has  yet  been  found  which  will  satisfy  the  whole  of  the  facts.  Under  these 
circumstances,  the  theory  suggested  by  Drs.  W.  and  D.  Asch  takes  its  place  amongst 
the  numerous  other  serious  attempts  to  ascertain  the  cause  of  this  very  elusive  property 
of  clays.  In  the  opinion  of  the  translator,  however,  the  present  application  of  the 
hexite-pentite  theory  to  plasticity  is  attempting  too  much.  The  hexite-pentite  theory 
is  so  valuable  in  its  relation  to  the  chemical  composition  of  clays  that  it  would  be  a 
pity  to  prejudice  its  acceptance  by  prematurely  extending  its  application.  When 
more  is  known  of  the  nature  of  plasticity,  it  is  not  improbable  that  the  value  of  this 
theory,  in  regard  to  plasticity,  may  be  much  greater  than  now  appears  to  be  the  case. 

The  Colour  of  Bricks  and  other  Articles  of  Burned  Clay 

The  red  colour  of  building  bricks  is  usually  attributed  to  the  presence  of  free 
ferric  oxide  in  the  burned  clay ;  that  of  Staffordshire  "  blue  "  bricks  and  clinkers  is 
generally  considered  to  be  due  to  the  production  of  a  ferrous  silicate  by  the  reducing 
action  of  the  kiln  gases  on  the  ferric  oxide  in  the  burned  clay. 

It  is,  however,  a  curious  fact  that  the  best  red  bricks  cannot  be  made  by  adding 
ferric  oxide  to  a  clay,  though  the  use  of  this  substance  does  produce  a  low  grade  of  red 
brick  with  a  very  irregular  colour.  Moreover,  ordinary  "  red  oxide  of  iron  "  dissolves 
readily  in  hydrochloric  acid,  but  the  colour  of  a  finely-ground  red  brick  is  not  removed 
by  cold  acid,  nor  can  such  a  powder  be  completely  bleached  even  by  boiling  with 
hydrochloric  acid  for  several  hours.  Again,  the  clay  used  for  blue  Staffordshire  bricks 
produces  goods  of  a  bright  red  colour  if  burned  in  an  oxidising  atmosphere,  the  blue 
colour  being  only  formed  when  reducing  gases  are  present.  If  the  temperature  of  the 
kiln  has  not  been  excessive,  and  the  atmosphere  is  made  strongly  oxidising,  the  blue 
colour  is  replaced  by  a  bright  red  one,  this  transformation  of  blue  and  red  and  vice 
versa  being  capable  of  being  repeated  indefinitely  as  long  as  the  temperature  is  care- 
fully regulated. 

The  generally  accepted  opinion  that  a  simple  ferrous  silicate  is  the  cause  of  the 
"  blue  "  colour  is  not  borne  out  by  synthetic  ferrous  silicates,  the  colours  of  the  latter 
being  quite  different. 

These  facts  all  point  to  the  colour  of  bricks  being  due  to  an  aluminosilicic  anhy- 
dride containing  iron  in  such  a  form  that  it  can  be  readily  converted  from  the  ferric 
to  the  ferrous  state  and  vice  versa.  The  structure  of  silicates  in  which  the  colour  is 
due  to  a  chromophore  group  containing  a  metallic  oxide  is  described  in  greater  detail 
in  a  later  section  on  "  Coloured  Glasses,"  in  which  the  state  of  combination  of  the  metal 
is  explained  by  the  aid  of  the  H.P.  theory. 

Seger730  and  others  have  exhaustively  investigated  the  relationship  between 
the  iron  contents  of  numerous  clays  and  the  colours  of  the  bricks  obtained  therefrom, 
but  have  not  been  able  to  find  any  definite  correlation  between  the  two.  In  many 
instances  clays  which  contain  5  per  cent,  or  more  of  iron  calculated  as  ferric  oxide, 
burn  to  a  pale  buff  or  primrose  tint,  whilst  other  clays  with  only  3  per  cent,  of  iron  oxide 
produce  bricks  of  a  strong  dark  red  colour.  The  lower-grade  fireclays  and  other  buff- 
burning  clays  do  not  contain  less  iron  than  red-burning  clays,  but  they  must  contain 
it  in  a  different  form.  There  is  evidence  in  support  of  the  view  that  in  buff-burning 
clays  the  iron  is  chiefly  in  the  form  of  pyrites,  whilst  in  red -burning  clays  it  is  in  the 
form  of  a  ferrosilicic  or  ferro-alumino-silicic  acid,  analogous  to  clay  in  which  one  or 
more  of  the  hydrogen  atoms  have  been  replaced  by  an  atom  of  iron.  Seger  also  found 
that  clays  rich  in  alumina  as  well  as  iron,  usually  burn  to  a  buff  rather  than  to  a  red 
tint. 

It  is  interesting  to  note,  in  this  connection,  that  if  a  red-burning  clay  is  washed 
with  dilute  hydrochloric  acid  a  large  part  of  the  colouring  matter  will  be  removed, 
and  if  the  clay  is  then  dried  and  burned  it  will  be  of  a  yellowish  red  colour.  No  treat- 


136  CONSEQUENCES   OF  THE   H.P.   THEORY 

ment  with  acid  has  yet  been  found,  however,  which  will  remove  all  the  iron  without 
destroying  the  clay. 

If  buff-burning  clays  are  brought  into  momentary  contact  with  flame  in  the  kiln 
a  reddish  tint  will  form  on  their  surface,  as  though  a  portion  of  the  combined  iron  were 
set  free  as  ferric  oxide.  No  satisfactory  explanation  of  this  phenomena  has  yet  been 
published,  as  the  amount  of  red  substance  formed  is  too  small  for  analysis  ;  the  pro- 
duction of  such  "  flame-flashed  "  goods  is,  however,  well  known  to  all  makers  of  fire- 
bricks. 

If  chalk  is  mixed  with  a  red-burning  clay,  the  bricks  produced  at  temperatures 
below  about  800°  C.  are  red,  but  above  this  temperature  the  chalk  reacts  with  the  iron 
compound  and  the  bricks  are  quite  white  and  might  be  supposed  to  be  quite  free  from 
iron.  The  nature  of  this  white  compound  of  lime,  iron  and  clay  has  never  been  ascer- 
tained, but  in  the  light  of  the  H.P.  theory  it  would  appear  as  if  the  lime  had  destroyed 
the  chromophore  group — forming  a  new  ferruginous  silicate — and  so  had  deprived  the 
iron  of  its  colouring  power. 

The  whole  subject  of  the  colour  of  burned  clays  is  of  great  technical  importance, 
but  hitherto  it  has  been  subject  to  so  many  assumptions  which  have  passed  as  explana- 
tions that  very  little  scientific  investigation  has  been  made.  Clay  workers  have  been 
content  to  accept  the  assumption  that  the  red  colour  of  certain  bricks  is  due  to  the  free 
ferric  oxide  in  the  clay  without  troubling  to  ascertain  how  it  is  that  5  per  cent,  of 
iron  oxide  is  without  effect  on  the  colour  of  the  raw  clay  and  yet  produces  such  an 
intense  colour  when  the  clay  is  burned.  That  some  change  must  occur  in  the  combina- 
tion of  the  iron  is  obvious  and  the  view  published  some  years  ago  by  the  translator  of 
the  present  work,  that  a  large  proportion  of  the  iron  occurs  in  the  form  of  ferrosilicic 
acid  (?nontronite,  H4  Fe2  Si2O9)  which,  on  heating,  is  decomposed  into  water,  silica  and 
free  ferric  oxide,  certainly  agrees  with  a  number  of  the  important  properties  of  red- 
burning  clays.  Whether  the  iron  is  in  the  form  of  a  ferrosilicic  acid  or  of  a  substituted 
group  in  an  aluminosilicic  acid  it  is,  at  present,  almost  impossible  to  determine  ex- 
perimentally.] 

XII 

The  Ultramarines 

Historical  Review 

Since  1828,  many  fruitless  attempts  have  been  made  to  ascertain 
the  true  cause  of  the  colour  of  the  ultramarines.  Those  investigators 
who  consider  ultramarine  to  be  simply  a  "  mixture  "  or  a  "  solid 
solution  "  have,  naturally,  endeavoured  to  find  a  "  colouring  principle," 
the  nature  of  which  varies  according  to  the  various  authors.  Thus, 
according  to  Gmelin246  and  Breunlin246,  the  "  colouring  principle  "  of 
ultramarine  is  sulphur  ;  Eisner247,  Kressler248,  Guyton  Morveau249, 
Priikner250,  and  Varrentrapp251  consider  it  to  be  iron  sulphide,  but 
Brunner252  has  contradicted  this  by  producing  a  blue  from  materials 
quite  free  from  iron,  which  colour  is  in  every  respect  equal  to  that 
produced  from  ferruginous  clays.  According  to  Unger253,  the  blue 
colour  of  ultramarine  is  due  to  nitrogen  compounds,  but  Biichner254 
has  disproved  this  by  showing  that  "  ultramarine  "  contains  no  nitro- 
gen. Stein255  has  suggested  that  ammonium  sulphide,  mixed  with  the 
ground  mass  in  a  state  of  "  molecular  fineness,"  is  the  colouring  matter 
of  "ultramarine,"  and  Rohland256  has  stated  that  "ultramarine" 
contains  a  "  colour-carrying  substance,"  or  chromophore,  whose 
composition  he  has  not  published. 

On  the  contrary,  those  investigators  who  consider  the  ultramarines 
to  be  definite  chemical  compounds  seek  for  the  source  of  the  colour  in 


HISTORICAL   REVIEW   OF   ULTRAMARINES  137 

the  arrangement  of  the  smallest  particles  of  this  compound,  i.e.  they 
regard  the  colour  of  ultramarine  either  as  a  constitutional  property  or 
seek  its  origin  in  definite  atomic  complexes  which  form  definite 
chemical  compounds  with  the  essential  constituent  (silicate)  of  the 
ultramarines.  Among  others  in  the  first  class  is  included  Hitter257,  who 
considers  that  "  there  can  be  no  question  of  a  colouring  principle,  as  the 
whole  of  the  ultramarine  forms  a  chemical  compound  because,  as 
previously  shown,  one  form  of  such  substances  may  be  colourless,  yet 
may,  under  certain  conditions,  be  converted  into  a  coloured  compound 
without  the  introduction  of  any  new  substance — a  comparatively  clear 
indication  that  here,  as  everywhere,  the  colour  is  due  to  the  arrange- 
ment of  the  "  smallest  particles." 

R.  Hoffmann258  is  one  of  those  who  consider  that  the  cause  of  the 
colour  is  to  be  found  in  definite  radicles  contained  in  the  ultramarine. 
He  has  referred  frankly  and  clearly  to  sulphonates  which  can  add  or 
lose  sodium,  oxygen,  and  sulphur,  forming  various  colours.259  "  These 
changes  occur  in  a  similar  manner  to  those  in  the  side  chains  of  organic 
compounds  ;  addition,  substitution,  and  subtraction  changes  may 
occur  without  destroying  the  combination  with  the  silicate  molecule." 

It  is  clear  that  Hoffmann's  conception  of  the  constitution  of 
ultramarine  is  the  one  which  most  closely  resembles  that  of  the  authors 
of  the  present  volume. 

In  this  connection,  the  following  extracts  from  Hoffmann's  inter- 
esting work  on  ultramarine  are  of  value  :  26°  "  for  the  present  it  is 
sufficient  to  state  that  the  formation  of  green  and  blue  ultramarines 
and  their  behaviour  towards  various  reagents  confirm  the  view  that  the 
sodium  added  in  the  form  of  oxide  must  be  more  firmly  united  to  the 
elements  of  the  kaolin  than  is  the  sulphide,  and  that  it  alone  takes  part 
in  the  further  conversion  of  white  into  blue  and  green  ultramarine. 
Consequently,  it  is  possible  to  distinguish  a  silicate  side  from  a  sulphide 
side  in  the  ultramarine  molecule  without  in  any  way  disturbing  the 
combination  of  the  elements  as  a  whole." 

Hoffmann261  was  also  the  first  to  claim  the  chemical  individuality  of 
ultramarine  and  to  confirm  this  by  means  of  microscopical  investiga- 
tion.262 He  was  also  the  first  to  show  that  it  is  not  correct  to  speak 
of  one  ultramarine,  but  rather  of  ultramarine  compounds  ;  he  en- 
deavoured to  classify  these  into  those  "  rich  in  silica  "  and  those 
"  poor  in  silica." 

The  view  that  there  are  several  ultramarines  and  that  some,  at  least, 
of  these  are  chemical  compounds,  has  been  independently  adopted  by 
Phillipp263,  Szilasi264,  Heumann266,  Guckelberger266,  etc.  At  the  same 
time,  it  should  be  noted  that  Hoffmann  has  doubted  the  chemical 
individuality  of  several  ultramarines,  including  "  ultramarine  green." 

"  Ultramarine  green  "  is  generally  understood  not  to  have  the 
properties  of  a  chemical  compound.267  It  is  considered  to  be  either  a 
mixture  of  ultramarine  blue  and  a  yellow  substance  or  as  ultramarine 
blue  to  which  sodium  sulphide,  etc.  has  adhered. 


138  CONSEQUENCES   OF  THE   H.P.   THEORY 

For  this  reason  Guckelberger268  examined  "  ultramarine  green  " 
microscopically  and  found  it  to  be  a  perfectly  uniform,  transparent, 
sea-green  substance.  No  traces  of  blue  particles  or  of  those  inter- 
mediate between  green  and  blue  were  discernible.  Hence,  Guckelberger 
concluded  that  "  ultramarine  green  "  is  a  single  chemical  compound. 

It  is  surprising  to  find  that,  as  early  as  1878,  B.  Hoffmann269 
expressed  an  opinion  on  the  nature  of  the  bond  of  the  sulphur-group  in 
the  ultramarines  which  is  very  similar  to  that  of  the  authors  of  the 
present  volume.  He  also  expressed  the  belief  that  part  of  the  oxygen 
in  the  silicate  molecule  is  replaceable  by  sulphur.  "  The  existence  of  a 
sodium  silico-aluminate  in  which  that  part  of  the  oxygen  which  is  in 
closer  combination  with  sodium  can  be  replaced  by  sulphur  —  such 
silico-sulphonates  behaving  like  free  sodium  monosulphonate  (from 
which  higher  sulphonates  may  be  produced  by  combination  with 
sulphur  and  loss  of  sodium,  without  the  silicosulphonate  being  decom- 
posed) —  would  be  sufficient  to  explain  the  formation  of  ultramarine  by 
the  ordinary  method  of  preparation  and  also  its  chemical  behaviour 
towards  other  substances." 

R.  Hoffmann734  endeavoured  to  find  satisfactory  structural 
formulae  for  white  ultramarine,  siliceous  blue  ultramarine,  etc.,  and 
for  this  purpose  made  use  of  the  silicate  formulae  proposed  by  K. 
Haushofer736  to  obtain  the  following  : 


Na—  O—  Al          >  Si—  S—  Na 


Na—  0—  Al  Si—  0—  Na 

White  ultramarine. 


0—  Al  <         Si—  S—  S—  Na 


Si 


O 


O— A] 


Na— O  0— Al 

Si 


/0\    ' 


Si— O 


O 

0_Al<0\s! 

Siliceous  blue  ultramarine. 


— S— Na 


Hoffmann   admitted,   however,   that   these   formulae   were    more 
fantastic  than  probable. 


THE   CONSTITUTION   OF   ULTRAMARINES  139 

A  New  Ultramarine  Theory 

The  formulation  of  the  authors'  new  hexite-pentite  theory  of  the 
constitution  of  the  silicates,  and  the  existence  of  an  extensive  literature 
of  ultramarine,  naturally  suggest  the  application  of  the  theory  to  the 
ultramarine  compounds.  The  absence  of  a  general  theory  of  the 
composition  of  the  silicates  appears  to  be  the  chief  reason  why  the  key  to 
the  chemical  constitution  of  the  ultramarines  has  not  yet  been  obtained, 
in  spite  of  the  innumerable  experiments  which  have  been  made. 

For  example,  the  following  hydro -aluminosilicate  : 

1111 


till 
H12H4(Si  •  Al  -  Al  •  SAi), 
contains  two  kinds  of  OH-groups  : 

1.  Aluminium  hexite  hydroxyl  (or  a-hydroxyl). 

2.  Silicon  hexite  hydroxyl  (or  s-hydroxyl). 

The  four  a-hydroxyls  must  obviously  behave  differently  from  the 
twelve  5-hydroxyls.  As  a  matter  of  fact,  the  hydrogen  in  the  a- 
hydroxyls  is  readily  replaced  by  monovalent  acid  radicles  such  as — N02 
— Cr02  •  OH,  — S02OH,  etc.  The  hydrogen  of  the  s-hydroxyls  is,  on 
the  contrary,  more  easily  replaced  by  basic  groups. 

In  the  hexite-pentite  theory  of  ultramarines,  the  a-hydroxyls 
play  a  special  part.  The  substitution  of  acid  radicles  for  hydrogen  in 
the  a-hydroxyls  is  specially  noticeable  as  a  characteristic  property  of 

the  compound  Na8H4(Si  •  Al  •  Al  •  Si)  first  observed  by  Silber  for  which 
no  explanation  has,  hitherto,  been  obtainable. 

On  heating  a  mixture  of  kaolin  with  an  excess  of  soda,  to  redness, 
and  washing  the  calcined  product  with  water,  Silber  obtained  the  com- 
pound : 

(Si2Al2Na208)6  =  Na12(Si  •  Al  •  Al  •  Si). 

If  this  substance  is  treated  with  dry  hydrochloric  acid  gas  at  150°, 
one-third  of  the  sodium  separates  out  as  sodium  chloride  and  there 

remains  the  compound  : 

Na  H    H    Na 

I      I       I      I 
Na— /\/\/\/\_ Na 

Si  Al   Al   Si 


I      i       I 
Na  H    H 


This  compound,  contrary  to  the  original  substance,  possesses  the 
remarkable  property  of  not  replacing  its  sodium  by  silver  when  treated 
with  a  solution  of  silver  nitrate.  Instead  of  replacing  the  sodium,  the 
silver  is  precipitated  as  oxide. 

Silber223  gives  this  substance  the  formula  Si6Al6Na4023,  but  he  has 


140 


CONSEQUENCES   OF  THE   H.P.   THEORY 


undoubtedly  overlooked  the  presence  of  hydrogen  in  it.  The  separation 
of  Na  by  the  action  of  HC1  can  only  occur  when  the  Na  is  replaced  by 
H,  for  a  temperature  of  150°  is  much  too  low  for  OH-groups  to 
separate  in  the  form  of  water. 

On  the  assumption  that  in  the  a-hydroxyls  the  hydrogen  can  be 

replaced  by  acid  radicles,  the  behaviour  of  the  compound  Na8H4(Si- 

Al  •  Al  •  Si)  with  AgNO3  may  readily  be  explained.  By  loss  of  Ag20 
and  H20  the  compound  : 

N02N02 

I       I 
O     O 

I       I       I 


N02N02 
is  formed. 

If  this  view  is  correct,  a  maximum  of  four  atoms  of  silver  can  be 
separated  for  each  twelve  atoms  of  silicon.  The  correctness  of  this 
consequence  of  the  theory  must  be  proved  experimentally. 

The  above  theory  permits  the  prediction  that  the  hydrogen  in  the 
a-hydroxyls  may  be  substituted  by  the  most  varied  monovalent 
inorganic  or  organic  acid  radicles,  and  that  in  all  compounds  of  the 

Si  •  Al  •  Al  •  Si  type,  only  four  of  these  acid  radicles  can  be  taken  up. 

The  aluminosilicates  in  which  the  hydrogen  of  the  a-hydroxyls  can 
be  substituted  by  monovalent  acids  or  acid  radicles  may  conveniently 
be  represented  by  the  terms  A  -aluminosilicates  or  2-aluminosilicates. 

The  mode  of  formation  of  the  .4 -aluminosilicates  may  be 
made  clear  by  means  of  a  few  examples.  The  production  of  these 
compounds  may  be  explained  as  due  to  splitting  off  the  elements 

/OH 
of  water.     Thus,  from    2   or    4   mols.    S02<f  QTJ   and   the   hydrate 

H12  •  H4(Si  •  Al  •  Al  •  Si),  the  following  A  -aluminosilicates  will  be  pro- 
duced : 

HO 


|OH|  |OHJ 

Oll|o[HJ 

I          I          I          I 


so/ 


THE  SULPHONATE  GROUPS  IN  ULTRAMARINES     141 

f\~LT         TTC\ 

\or\ 
i    ,-=rr/b°2  0!Hl     lOHl 

O 

S02/\S02 

i   i 

I        I        I 


_)    __) 

0|H]  0|H| 


so 


S02    S02 


c. 


S02\/S02 

o 


D. 


The  compounds  A,  B,  C,  D  are  acids  or  acid  anhydrides. 

The  hydrogen  atoms  of  the  sulpho-groups  in  A  and  C  and  the  s- 
hydroxyl  groups  may  be  partially  or  completely  replaced  by  a  base, 
whereby  acid  or  normal  salts  will  be  produced. 

In  ultramarines,  the  group 

0 


so,- 

0 


=  S207 


(a) 


plays  a  special  role.  This  atomic  complex  has  the  power,  under  certain 
conditions,  to  split  off  oxygen  atoms  and  to  take  them  up  again,  or  to 
replace  them  partially  or  completely  by  sulphur  atoms.  Thus,  there 
may  be  formed  from  S207  the  following  : 

Sulphonates 


0 

o 

s 

S02-S02 

so/Nso 

so—  so 

s/\s 

s—  s 

SS/\SS2 

O       0 

0          O 

A    6 

1        1 
O       0 

a  A 

o       o 

1        1 

1          1 

1        1 

1        1 

1    1 

1          1 

S206 

S205 

S204 

S203 

S202 

S702 

(b) 

(c) 

(d) 

(e) 

w 

(g) 

0 

o 

s 

*- 

s 

ss/^ss, 

ss,/\ss, 

SS2/\SS2 

SS2-S£ 

52    S/^ 

VS2    S2  —  S2 

d      A 

4     b 

1             1 

s        s 

s      s 

g 

Q             QJ            Q 

bob 

1          1 

1          1 

1           1 

1        1 

1 

1      1      1 

S603 

s?o 

S9 

S8 

S7 

S6 

So 

(k) 

(1) 

(m) 

(n) 

etc.  etc. 

142 


CONSEQUENCES  OF  THE   H.P.   THEORY 


The  sulphonates  are  very  labile  radicles  and  can  be  converted  into 
one  another,  under  certain  conditions,  by  the  loss  or  addition  of  oxygen 
or  sulphur  atoms  or  by  the  substitution  of  atoms  of  oxygen  for  those  of 
sulphur  and  vice  versd.  The  atomic  complexes  a,  6,  c,  d,  e,  etc.  are 
anhydrosulphonates,  but  they  may  also  enter  the  above  ^4-alumino- 
silicates  A  and  C  as  hydro-compounds. 

The  Sulphonates  as  Chromophores 

The  study  of  the  A-  and  2-aluminosilicates  containing  sulphonate 
groups  has  shown  that  these  substances  may  be  regarded  as  chromo- 
phores  in  the  sense  in  which  this  term  is  used  in  Witt's  theory.* 

The  introduction  of  a  sulphonate  group  in  this  way  into  a  hydro- 
aluminosilicate  is  not  sufficient  to  form  a  coloured  body.  There  must 
also  be  one  part  of  the  hydrogen  of  the  s-hydroxyls  or  the  total 
hydrogen  of  the  A-  or  2-hydro-aluminosilicates  replaced  by 
mono-  or  divalent  basic  atoms.  Such  colour-stuffs  may  be  termed 
"  ultramarines." 

Ultramarines  are,  therefore,  in  terms  of  the  hexite  theory,  such 
compounds  as  : 

ONa  ONa 


etc.  etc. 


Following  the  suggestion  of  M.  Schiitz224  it  is  convenient  to  regard 
the  change  from  yellow  to  orange,  red,  bluish  violet,  violet,  blue,  blue- 
green  and  green  as  a  deepening  of  the  colour  ;  the  reverse  change  from 
blue-green  to  blue,  etc.  as  a  lightening  of  the  colour. 

R.   Nietzki225  has   formulated  a  law  representing  the  relation 

*  Witt's  theory  is  described  in  further  detail  in  a  later  chapter  on  the  chemical 
constitution  of  coloured  glasses,  p.  246. 


THE   SULPHONATE   GROUPS   IN   ULTRAMARINES     143 

between  the  change  of  shade  in  a  pigment  and  its  composition.  Accord- 
ing to  this,  the  pigments  of  the  simplest  constitution  are  yellow  ;  with 
increasing  molecular  weight  the  yellow  colour  changes  into  red,  violet 
and  blue.  Later  researches  by  Kriiss  and  S.  Oeconomides226,  H.  W. 
Vogel227,  and  E.  Koch228  have  shown  that  Nietzki's  law  is  of  general 
application,  but  that  there  are  certain  exceptions  to  it  in  which  an 
increase  in  the  molecular  weight  accompanies  a  lightening  instead  of  a 
darkening  of  the  colour. 

With  increasing  molecular  weight,  the  sulphonate  group  can 
produce  either  a  deepening  or  a  lightening  of  the  colour. 

As  it  is  not  sufficient  merely  to  have  a  sulphonate  chromophore  in 
order  to  form  a  hydro-aluminosilicate  pigment,  and  the  introduction 
of  a  base  into  an  acid  is  necessary,  it  is  clear  that  the  nature  of  the 
base  must  exercise  an  important  influence  on  the  shade.  An  increased 
molecular  weight  may  thus  cause  either  a  lightening  or  darkening  of 
the  colour.  In  all  probability,  the  molecular  weight  of  the  original 
substance  of  the  pigment  (i.e.  the  aluminosilicate  itself)  is  also  of 
importance  in  connection  with  the  shade  of  colour  produced. 

Enough  has  been  said  to  enable  the  various  facts  relating  to  ultra- 
marines to  be  explained  in  a  simple  manner.  Apart  from  this,  however, 
the  theory  shows  the  manner  in  which  further  investigations — both 
practical  and  academic — may  most  usefully  be  carried  out  in  connec- 
tion with  these  highly  important  pigments. 

The  Hexite  Theory  of  Ultramarines  and  the  Facts 

From  the  ultramarine  theory  developed  above,  a  series  of  Conse- 
quences result.  It  is  important  to  see  how  these  agree  with  the  facts. 

A 

Theoretically,  the  composition  of  the  ultramarines  may  be  pre- 
dicted. It  is,  in  fact,  highly  interesting  to  calculate  the  formulae  of  a 
large  number  of  analyses  in  order  to  see  how  far  they  confirm  the 
Consequences  of  this  theory. 

Most  analyses  of  ultramarine  have  not  been  calculated  into  formulae, 
and  those  which  have  been  given  often  show  wide  differences  between  the 
calculated  and  ascertained  values.  This  is  considered,  by  most  chemists, 
as  being  less  due  to  errors  in  calculating  the  formulae  than  to  impurities 
in  the  material. 

The  calculation  of  these  formulae  showed  that  ultramarines  of  the 
following  types  have  already  been  prepared  (see  Appendix)  : 

1.  Si  •  Al  •  Al  •  Si, 

2.  Si-Al-sVAl-Si, 

3.  Si  •  Al .  Si  •  Al  •  §T, 

4.  Si-Al-Si, 

5.  Si  •  Al  •  Si. 


144 


CONSEQUENCES   OF  THE   H.P.   THEORY 


From  type  1,  for  example,  ultramarines  of  the  following  types  have 
been  produced  : 

O 

SO   SO 


Si 


Al 


Al 


Si 


\ 
i 


/\/' 


(a)     Rm(Si12Al12On)(S207)2. 


I        I 
SO    SO 

\/ 

O 

(b)    Rm(Si12Al12On)(S205)2. 


s 


(c)    Rm(Si12Al12On)(S202), 


(d)    Rm(Si12Al12On)(S20)2. 


(e)    Rm(Si12Al12On)(S2)2. 

Summary  of  Ultramarines  obtained,  arranged  according  to  the  foregoing 

Types 

(a)  Rm(Si12Al12On)(S207)2. 

1.  Na12(Si12Al12046)  •  S4014. 

(b)  Rm(Si12Al12On)  •  S4010. 

2.  Nan.5K0.5(Si12Al12046)  •  S4O10  •  ONa2, 

3.  Ag16(Si12Al12048)  •  S4010  •  ONa2(H20)4, 

4.  Pb8(Si12Al12048)  •  S4010  •  ONa2(H20)8, 

5.  Zn8(Si12Al12048)  •  S4010  •  ONa2(H20)16, 


THE   CONSTITUTION   OF  THE   ULTRAMARINES       145 

6.  Ag12(Si12Al12046)  •  S509  •  OAgNa, 

7.  Ag15Na(Si12Al12048)  •  S5O9, 

8.  Na12(Si12Al12046)  •  S608. 


(c)     Bm(Si12Al12On)  •  S404. 

9.     Na16(Si12Al12048)  •  S404(H20)2, 
10.     Na12(Si12Al12046)  •  S503  •  ONa2. 


(d)    Rm(Si12Al12On)  -  S402. 

11.  Na12(Si12Al12O46)  •  S402, 

12.  Na12(Si12Al12046)  •  S402  •  Na2, 

13.  Na12(Si12Al12046)  •  S402  •  Na4, 

14.  Na12(Si12Al12046)  •  S402  •  Ag4, 

15.  Na6Ag6(Si12Al12046)  -  S402  •  Ag4. 


(e)    Rm(Si12Al12On)  •  S4. 

16.  Nan.5K0.5(Si12Al12046)  •  S4Na2, 

17.  Na16(Si12Al12048)  -  S4Na2, 

18.  Na12(Si12Al12046)  •  S4Na4. 


Ultramarines  of  other  types  are  arranged  according  to  their  sulphonates. 
The  following  additional  pigments  have  been  produced  : 

(a)     Rm(AlpSirOn)  '  S4014. 

19.  Na14(Si16Al12055)  •  S909, 

20.  Na16(Si16Al12056)  •  S909, 

21.  Na4(Si12Al6034)  •  S603  •  ONa2, 

22.  Na6(Si10Al6081)  •  S603. 

(6)    Rm(AlpSirOn)  •  S4010. 

23.  Na16(Si16Al12056)  •  S1004  •  02Na4. 

(c)    Rm(AlpSirOn)  •  S408. 

24.  Na14(Si18Al12059)  •  S12, 

25.  Na18(Si18Al12061)  •  S12, 

26.  Na20(Si18Al12062)  •  S12, 

27.  Na12(Si16Al12056)-S12. 


146  CONSEQUENCES  OF  THE   H.P.  THEORY 

(d)    Rm(AlpSirOu)-S402. 

28.  Na8(Si12Al6038)  -  Sff 

29.  Na16(Si18Al12060)  •  S6, 

30.  Na18(Si18Al12061)  •  S50. 

The  above  ultramarines  exist  both  theoretically  and  actually. 
Other  corresponding  compounds  must  be  produced  sooner  or  later. 

If  the  views  just  expressed  with  regard  to  the  constitution  of 
ultramarines  are  correct,  these  substances  can  only  be  produced  from 
hydro-aluminosilicates  with  a-hydroxyls,  and  not  from  acids  of  the 
following  types  : 


x 
I.    il;-Si  2.    At-Si  3.    Al-Si  and  4. 

si  si 


.  . 

Xsi  xsi  x 


as  the  latter  contain  no  a-hydroxyls. 

Ultramarines  of  these  latter  types  are,  as  yet,  unknown,  and  any 
attempts  to  produce  them  must  prove  abortive  if  the  hexite-pentite 
theory  is  correct. 


Many  ultramarines  of  the   greatest   diversity  of  colour  are  in 
agreement  with  the  theory.     Thus  : 

1.  According  to  Zeltner229,  violet  ultramarine  may  be  obtained 
from  the  blue  or  green  varieties  if  chlorine  or  other  halogen  and 
hydrogen  is  passed  through  the  given  ultramarine  at  160-180°,  NaCl 
being  separated. 

2.  According  to  Hoffmann230,  a  purple-red  or  violet  pigment  may 
be  obtained  from  blue  or  green  ultramarine  by  treatment  with  acids  or 
salts  and  air  at  a  high  temperature.     A  separation  of  the  base — 
also  probably  of  the  sulphonate  group — occurs. 

3.  J.  Phillipp231  obtained  a  blue  ultramarine  by  treating  green 
ultramarine  with  water  at  160°,  and  concluded  that  sodium  sulphide 
was  liberated  in  the  process. 

4.  Gmelin232  had  previously  shown  that  blue  ultramarine,  when 
heated  in  a  current  of  hydrogen,  is  converted  into  red  ultramarine  with 
the  liberation  of  H2S. 

5.  In  the  following  compounds,  with  the  same  chromophore  and  the 
same  silicate  nucleus,  but  with  a  variable  proportion  of  base,  the 
deepening  of  the  colour  with  increasing  molecular  weight — in  accord- 
ance with  Nietzki's  law  (p.  142) — is  readily  observable. 

Na14(Si18Al12059)S12  is  red, 
Na18(Si18Al12061)S12  »  violet,  and 
Na20(Si18Al12062)S12  „  blue. 


THE   CONSTITUTION  OF  ULTRAMARINES 

The  possible  existence  of  isomeric  ultramarines  follows  naturally 
from  the  theory.  Thus,  there  are  four  possible  isomers  for  a  compound 
with  the  formula  : 

Na12(Si12Al12046)S604Na2, 

as  may  be  seen  from  the  following  structural  formulae  : 


0-SNaO-SNa 
3. 


Si       Al      Al       Si 

\X\x 


•SNaO-SNa 
2. 


0-SNa-SNa 
4. 


The  results  of  anumber  of  analyses  by  R.  Hoffmann233,  Heumann234, 
and  Phillipp235  agree  with  the  last-mentioned  formula.  In  spite 
of  the  fact  that  all  the  ultramarines  examined  by  these  investigators 
had  the  same  composition,  they  varied  in  their  characteristics,  the 
ultramarines  of  Hoffmann  and  Heumann  being  blue  and  that  of 
Phillipp,  green.  Hence  at  least  two  isomers,  out  of  those  possible,  are 
known. 

Further  studies  of  these  pigments  must  eventually  lead  to  the 
discovery  of  new  isomers,  the  composition  of  which  can  be  predicted. 
Thus,  there  are  three  possible  isomers  of  the  compound 

Na16(Si12Al12048)  -  S404, 
with  the  following  structural  formulae  : 


148  CONSEQUENCES  OF  THE   H.P.  THEORY 

S  — S  0—0  S  — S 


3. 


On  treating  a  given  ultramarine  with  an  aqueous  solution  of  a  salt, 
e.g.  the  compound 

S  — S 
Na    6      O      Na 


Na2= 


Si    Al 


Al 


Si 


/\/ 

a    O 


=Na2 

!=Na2 


-i 


with  BaCl2,  SrCl2,  ZnS04)  AgN03,  etc.,  a  substitution  of  the  sodium  by 
barium,  strontium,  zinc  or  silver,  etc.  may  occur  or  the  sulphonate 
group  may  pass  into  the  new  compound.  The  sulphonates,  as  already 
mentioned,  are  very  labile  radicles  and  can  easily  unite  with  or  throw 
off  oxygen,  so  that  it  is  by  no  means  impossible  that  the  sulphonate  of  a 
new  compound  may  be  either  rich  or  poor  in  oxygen. 

Szilasi236  and  Heumann237  have  reached  the  same  conclusion  in 
their  investigation  of  the  behaviour  of  ultramarine  compounds  and 
solutions  of  salts.  Szilasi  studied  the  behaviour  of  three  green  ultra- 
marines (see  Appendix) — one  made  at  Budapest  and  the  two  others 
at  Nuremberg.  As  it  happened,  all  three  samples  had  the  same  com- 
position, viz.  : 

S— S 


A. 


_/\/\/\/\= 
Si    Al    Al     Si  I       aq. 


S404(H20)2. 


THE  CONSTITUTION   OF  ULTRAMARINES 


149 


By  treating  this  compound  with  a  solution  of  AgN03,  Pb(N03)2  and 
ZnS04,  Szilasi  obtained  the  following  ultramarines  : 

ONa   ONa 

SO      SO 


B. 


aq. 


SO     SO 


o 

Ag16(Si12Al12048) 
Pb8(Si12Al12048) 
Zn8(Si12Al12048) 


S4010ONa2(H20)4, 
S4010ONa2(H20)8, 
S4010ONa2(H20)16. 


The  mode  of  formation  of  compound  B  from  A  is  easily  seen.  On 
the  silicate  side  there  is  a  replacement  of  sodium  by  Ag,  Pb  or  Zn, 
whilst  one  sulphonate  has  added  oxygen  and  the  other  oxygen  and 
Na20.  The  addition  of  Na2O  is  due  to  the  fact — noted  by  several 
investigators — that  sodium  ultramarines,  on  treatment  with  water, 
lose  part  of  their  sodium  in  the  form  of  caustic  soda. 

That  the  sulphonates  can  lose  oxygen  and  Na20  in  aqueous  solution 
is  shown  by  the  fact  that  Szilasi  was  able  to  reproduce  the  original 
sodium  salt  A  from  the  silver  salt  B  1,  with  the  structural  formula 
B,  by  treating  the  latter  with  sodium  iodide. 

Heumann  examined  a  blue  ultramarine  from  Marienberg,  the 
analysis  of  which  (see  Appendix,  Analysis  No.  10)  corresponds  to  the 
formula  : 


C. 


Na12(Si12Al12046)  •  Na2S504. 


150  CONSEQUENCES   OF  THE  H.P.  THEORY 

This  sodium  ultramarine  was  heated  with  silver  nitrate  in  a  sealed 
glass  tube  at  120°  for  seven  hours  and  formed  a  yellow,  silver  ultra- 
marine with  a  composition  corresponding  to  : 

0 


SO   S 


O 

A 


B.  |  Si  I  Al    Al  |  Si 

"YYW 

o    o 

so  so 

\/ 

s 

AgMNa(Si12Al12048)  -  S609. 

The  sulphonate  groups  in  this  case  were  oxidised  ;  they  added 
oxygen  and  lost  Na2O.  The  silicate  side  took  up  more  base  than 
compound  C,  as  shown  in  formula  D.  Such  cases  have  frequently 
been  observed  in  the  formation  of  complex  silver  and  thallium  salts 
(p.  19). 

To  all  appearances,  Heumann  was  able  to  reproduce  the  original 
sodium  salt  by  heating  the  silver  salt  for  eight  hours  at  130°- 140°  with 
a  solution  of  sodium  chloride,  but,  unfortunately,  no  analysis  of  this 
blue  compound  is  available. 

F 

If  the  ultramarines  are  really  derivatives  of  clays  and  are  formed 
in  the  manner  indicated  by  the  hexite  theory,  the  possibility  of  the 
formation  at  temperatures  above  the  vitrification  point  of  the  clay 
must  diminish  with  the  amount  of  polymerisation  which  occurs  and 
must  cease  entirely  at  the  temperature  at  which  the  clay  fuses,  as  at 
that  temperature  clays  no  longer  contain  a-hydroxyl.  On  the  other 
hand,  it  must  be  possible  to  destroy  the  colour  of  any  ultramarine  by 
heating  it  to  a  sufficiently  high  temperature. 

Knapp  and  Ebell238  have  shown  that  as  soon  as  the  temperature 
of  an  ultramarine  reaches  that  of  incipient  vitrification,  the  possibility 
of  its  remaining  blue  diminishes  and  it  ceases  entirely  at  the  fusion 
point  of  the  material. 

Gmelin239  has  shown  that  the  colour  of  ultramarine  may  easily  be 
destroyed  by  excessive  or  prolonged  heating. 

C.  Stolzel240  heated  blue  ultramarine  to  redness  for  a  long  time  in 
a  platinum  crucible  and  noted  that  the  colour  gradually  weakened  and 
that  a  white  product  was  finally  obtained.  A  green  ultramarine,  when 
similar!/"1  ^  ated,  showed  no  diminution  in  colour.  At  first  it  darkened, 


THE   CONSTITUTION   OF  ULTRAMARINES  151 

but  then  showed  so  great  a  stability  that  after  several  hours'  "  powerful 
heating  "  no  further  change  could  be  noticed.  In  all  probability,  the 
vitrification  point  of  the  green  ultramarine  examined  by  Stolzel  was 
above  the  "  red  heat  "  to  which  it  was  exposed  ;  this  accounts  for 
the  colour  remaining  unaffected.  Further  experiments  will  show 
whether  the  destruction  of  the  colour  of  a  number  of  ultramarines, 
which  are  stable  at  red  heat,  occurs  at  a  higher  temperature.  Accord- 
ing to  the  hexite  theory,  this  must  necessarily  occur. 

G 

The  separation  of  a  sulphonate  group  in  an  ultramarine  must 
result  in  a  destruction  of  the  colour.  This  is  necessarily  the  case. 
Dilute  acids,  such  as  hydrochloric  acid,  effect  a  separation  of  the 
sulphonate  group  and  produce  a  colourless  mass. 

H 

If  the  ultramarines  are  real  derivatives  of  clays,  strong  acids  must 
not  only  effect  a  separation  of  the  sulphonate  groups,  but  must  also 
affect  the  silicate  nucleus  and  convert  it  into  a  compound  of  the  most 
stable  type,  gelatinous  silica  usually  separating  out.  No  experiments 
in  this  direction  are  yet  available.  The  truth  of  these  conclusions — at 
at  any  rate  as  regards  the  separation  of  gelatinous  silica — appears  to  be 
confirmed  by  Eisner241,  who  treated  two  ultramarines — one  blue  and 
one  green — with  hydrochloric  acid.  Both  lost  their  colour,  sulphuretted 
hydrogen  being  evolved  and  gelatinous  silica  separated. 


The  authors'  ultramarine  theory  gives  a  maximum  content  of 
monovalent  bases  in  these  substances.  So  far  as  the  analyses  studied 
by  the  authors  are  concerned,  no  ultramarine  is  known  with  a  higher 
content  of  bases  than  the  maximum  shown  by  the  hexite-pentite 
theory. 

K 

The  theory  also  demands  a  minimum  molecular  weight  for  ultra- 
marines. In  this  connection  it  is  interesting  to  note  that  Guckel- 
berger242 — in  studying  the  ratio  H2S  :  S  :  S02  in  the  decomposition  of 
ultramarines  by  acids — has  also  arrived  at  the  conclusion  that  the 
molecular  weight  of  "  ultramarine  blue  "  is  greater  than  that  of  an 
atomic  complex  with  6  silicon  atoms,  and  that  it  is  a  multiple  of  Si6. 
This  view  agrees  with  the  theory  proposed  by  the  authors  of  the 
present  volume. 

L 

It  also  follows  from  the  theory,  that  the  sulphonates  form  definite 
chemical  compounds  with  silicate  nuclei.  Ritter243  has  reached  the 
same  conclusion  experimentally.  By  the  action  of  chlorine  gas  at 


152 


CONSEQUENCES   OF  THE   H.P.   THEORY 


300°  on  the  so-called  white  ultramarine,  Hitter  has  shown  that  only 
a  small  quantity  of  sodium  chloride  is  formed.  From  this  he  rightly 
concluded  that,  in  the  ultramarines,  the  sulphonates  are  in  true 
chemical  combination  with  the  silicates,  as  any  free  sulphide  com- 
pounds present  would  be  completely  decomposed  by  chlorine. 

R.  Hoffmann244  is  of  the  opinion  that  the  sulphonate  groups 
behave  similarly  to  free  sulphides,  but  are  not  quite  the  same  as  the 
latter  as  "  they  show  a  greater  stability  in  the  silicate  compounds." 

Analogy  between  Ultramarines  and  Sodalites 

In  concluding  these  observations,  it  is  interesting  to  note  the  mode 
of  formation  of  a  number  of  compounds,  the  constitution  of  which  is 
analogous  to  that  of  the  ultramarines. 

The  assumption  that  some  normal  salts,  e.g.  Na2S04,  Na2W04, 
NaN03,  etc.,  contain  "water  of  constitution,"  when  in  aqueous 
solution,  is  quite  reasonable,  as  the  formation  of  such  hydrates  is 
extremely  probable  (p.  267).  If  it  is  accepted,  there  is  a  possibility  of 
forming  compounds  with  these  salts  and  an  aluminosilicate  correspond- 
ing to 

Na2  OH  OH  Na2 
B       I       I 


Na. 


6  Na20  •  2  H20  •  6  A120£ 
A 


12  Si05 


If  water  is  lost,  the  constitution  of  the  resultant  substances  may 
be  represented  by  the  formulae  : 


Na 


2      Na2 

II    '    I        I       II 

Na_/\/\/v\ 


Si 


Al 


Al    Si 


— Na 


/\/\/\/ 
Na2  OH  OH  Na2 
B 


— Na 


Na2 


the  sign  2  representing  a  molecule  of  a  given  salt  (Na2S04,  Na2W04, 
NaN03,  etc.). 

Thugutt  (p.  60)  has  actually  obtained  a  series  of  these  compounds 
which  may  be  termed  "  atomic  compounds  "  (p.  59).  From  this  atomic 
expression  of  the  constitution  of  the  sodalites  it  follows  that  a  molecule 
of  silicate  A  can  combine  with,  at  most,  4  molecules  of  S.  This 
Consequence  of  the  theory  is  confirmed  by  the  facts,  and  no  sodalite  is 


CRITICAL   REVIEW   OF   CEMENT  THEORIES  153 

yet  known  which  contains  more  than  4  molecules  of  2  to  one  of  A  (see 
the  series  of  Thugutt's  sodalites  on  p.  60). 

Theoretically  it  is  also  possible  that  the  aluminosilicate  A  and  other 
aluminosilicates  with  a-hydroxyls  may  not  only  combine  with  simple 
compounds  and  salts  of  the  kinds  mentioned — conveniently  termed  A 
(acid-)  and  2  (salt-)  sodalites — but  also  with  complex  acids  and  their 
salts. 

The  formation  of  sodalites  (A-  and  2-sodalites)  of  the  latter  kind 
occurs  in  the  so-called  porcelain  cements  (p.  215). 

Thugutt's  sodalites  and  the  porcelain  cement  sodalites  may  there- 
fore be  regarded  as  analogous  to  the  ultramarines. 


XIII 

A  New  Theory  of  Hydraulic  Binding  Materials,  with  special  reference 

to  Portland  Cement 

The  various  substances  known  as  "  Portland  cement  "  form  only 
one  division  of  the  so-called  hydraulic  binding  materials,  the  others 
being  known  as  trass,  puzzolans,  hydraulic  limes,  Roman  cement,  slag 
cements,  etc.  Of  all  these,  the  Portland  cements  are  the  most  important 
and  valuable  hydraulites.  *  Like  the  ultramarines,  innumerable  theories 
have  been  proposed  to  explain  their  chemical  nature,  but  none  of  these 
theories  is  completely  satisfactory. 

If,  as  may  be  taken  for  granted,  the  solution  of  the  problem  is  to 
be  found  in  the  chemical  nature  of  the  silicate  cements  and  in  the 
chemical  constitution  of  the  substances  (silicates)  from  which  they 
are  derived,  any  attempt  to  apply  the  new  hexite-pentite  theory 
to  the  constitution  of  these  cements  must  be  of  exceptional  interest. 
If  the  new  theory  should  prove  to  be  of  general  applicability  to  the 
silicate  cements  it  would  not  only  solve  one  of  the  most  interesting 
problems  of  inorganic  chemistry,  but  the  fact  that  it  could  afford  such 
a  solution  would  be  of  enormous  value  to  the  new  theory  itself. 

Before  endeavouring  to  apply  the  new  theory  to  the  hydraulic 
binding  materials,  it  is  desirable  to  review  briefly  and  critically  the 
various  theories  now  in  existence  concerning  cement,  and  to  state  in 
some  detail  the  nature  of  the  problem  the  solutions  to  which  hitherto 
suggested  have  proved  so  unsatisfactory. 

Historical  and  Critical  Notes  on  previous  Theories  relating  to  Cements 

The  artificial  production  of  Portland  cement  had  scarcely  been 
discovered  when  a  question  arose  as  to  the  cause  of  hardening  f  of 

*  A  hydraulite  is  a  substance  which,  when  mixed  with  water  to  form  a  stiff  paste, 
sets  and  becomes  hard  like  a  cement. — A.  B.  S. 

f  In  English-speaking  countries  the  "  setting  "  and  "  hardening  "  of  cements  are 
treated  as  distinct.  In  the  present  volume,  the  term  "  hardening  "  is  used  to  include  all 
the  processes  which  occur  from  the  time  the  soft  material,  made  by  mixing  the  cement  with 
water,  begins  to  set  to  the  time  when  the  mass  attains  its  maximum  hardness. — A.  B.  S. 


154  CONSEQUENCES  OF  THE   H.-P.  THEORY 

cements  generally.  A  French  engineer,  Vicat270,  who  had  paid  much 
attention  to  cements,  set  to  work  to  investigate,  and  eventually  con- 
cluded that  the  hardening  was  due  to  the  combination  of  the  cement 
with  water.  A  closer  investigation  showed  that  there  are  several 
difficulties  in  the  way  of  accepting  this  hypothesis,  some  substances, 
which  were  known  to  combine  with  water,  never  hardening  like  cement. 
Thus,  the  zeolites  are  hydrous  aluminosilicates  which,  after  being 
deprived  of  water,  can  absorb  it  again  from  the  air,  though,  as  Fuchs 
has  shown,  such  dehydrated  zeolites  do  not  harden  under  water. 
Again,  quicklime  is  well  known  to  combine  with  water,  yet  the  com- 
bination does  not  produce  a  hard,  solid  mass,  but  only  a  soft,  friable 
powder.  Fuchs271  therefore  sought  for  another  explanation  of  the 
cause  of  the  hardening,  and  eventually  made  the  remarkable  discovery 
— since  repeatedly  confirmed — that  only  those  aluminosilicates  which, 
on  treatment  with  acids,  produce  gelatinous  silica,  possess  the  property 
of  hardening  with  lime  and  water.  Fuchs  concluded  that  hardening  is 
a  chemical  process  in  which  part  of  the  lime  and  the  "  attackable," 
"  soluble  "  silica  unite,  on  burning,  to  form  a  calcium  silicate. 
Indeed,  Fuchs  went  so  far  as  to  state  the  composition  of  the  silicate 
which  he  supposed  was  formed.  As  no  facts  in  opposition  to  this 
theory  were  known,  it  was  not  only  accepted  readily,  but  was  used  to 
great  advantage.  Pettenkoffer272 — an  energetic  supporter  of  this 
theory — even  suggested  that  Fuchs  had  so  completely  solved  the 
problem  that  no  further  investigation  was  necessary !  Feichtinger273, 
however,  sought  for  experimental  proofs  of  Fuchs'  theory,  and  believed 
he  had  found  it  in  the  following  fact :  if  the  hardening  is  due  to  a  com- 
bination of  soluble  silica  and  free  lime,  the  mixture  must  lose  soluble 
silica  in  proportion  to  the  amount  of  hardening  which  has  occurred. 
This  fact  he  confirmed  on  several  occasions. 

Fuchs'  theory  was  published  before  the  discovery  of  Portland 
cement,  and,  when  applied  to  the  latter,  difficulties  at  once  arose.  One 
of  these  difficulties  was  that  in  Portland  cement  the  chemical  behaviour 
suggests  that  the  whole  of  the  lime  is  in  a  combined  state  and  that  no 
free  lime  is  present  to  combine  with  the  soluble  silica.  This  was  one  of 
the  first  facts  observed  to  be  opposed  to  Fuchs'  theory.  Winkler274 
then  found  it  necessary  to  devise  a  new  theory  for  these  hydraulites,*  and 
at  once  assumed  that  in  the  newer  cements  the  hardening  was  not  so 
much  the  result  of  a  new  compound  of  lime  and  silica  as  of  the  separa- 
tion of  lime  from  a  compound  previously  formed.  He  retained  Fuchs' 
theory  for  silicate  cements  containing  free  lime  (Roman  cements)  and 
concluded  that  in  Portland  cements  the  liberation  of  lime  occurred 
until  the  same  calcium  silicate  was  obtained  as  Fuchs  had  found  to  be 
necessary  in  the  other  hydraulites. 

Feichtinger275,  on  the  contrary,  opposed  Winkler 's  theory,  and 
maintained  that  Portland  cements  contain  free  lime  ;  to  this  extent  he 

*  See  the  first  footnote  on  the  previous  page. 


PORTLAND  CEMENT  THEORIES  CRITICISED         155 

supported  Fuchs'  theory.  Nevertheless,  it  is  possible  to  draw  pre- 
cisely the  opposite  conclusions  from  Feichtinger's  experiments,  i.e.  the 
absence  of  free  lime  in  Portland  cement.  He  endeavoured  to  explain 
the  inconsistency  of  his  theory  with  the  facts  by  means  of  a  new  and 
improbable  hypothesis,  viz.  that  the  particles  of  free  lime  are  so 
coated  over  with  molten  cement  that  a  considerable  amount  of  time 
is  needed  before  the  presence  of  the  free  lime  becomes  noticeable. 
Feichtinger  examined  various  kinds  of  hydraulic  limes,  including 
those,  like  Portland  cement,  in  which  the  whole  of  the  lime  is  chemi- 
cally combined,  and  those,  like  Roman  cements,  which  contain  free 
lime.  Both  are  readily  distinguished  by  their  behaviour  towards 
water  ;  the  former,  on  hydration,  show  a  scarcely  noticeable  rise  in 
temperature,  whilst  the  latter  show  an  unmistakable  development  of 
heat .  Furthermore,  Portland  cements  after  a  given  period  of  hydration 
show  no  Ca(OH)2,  whilst  in  the  Roman  cements  this  substance  may  be 
detected  as  soon  as  water  is  added.  This  is  in  direct  contradiction  to 
Fuchs'  theory.  In  order  to  retain  this  theory,  Feichtinger  had  recourse 
to  the  improbable  hypothesis  mentioned  above. 

Winkler 276  has  argued  that  the  behaviour  of  Portland  cement  towards 
an  alcoholic  solution  of  phenolphthalein  shows  that  the  whole  of  the 
lime  is  in  a  chemically  combined  state,  as  the  smallest  trace  of  free 
lime  would,  if  present,  turn  the  indicator  red.  In  reality,  no  such  red 
colour  is  produced.  Fuchs'  theory  is  inconsistent  with  the  possibility 
of  regenerating  the  cement  from  the  set  or  hardened  mass,  though  this 
possibility  may  be  inferred  from  Feichtinger's  experiments,  as  will  be 
shown  later.  No  agreement  was  ever  reached  by  Feichtinger  and 
Winkler  :  each  retaining  his  own  opinion  to  the  last.  This  shows  how 
strong  was  the  influence  of  Fuchs'  theory  on  Feichtinger. 

No  absolute  answer  to  the  question,  "  Does  Portland  cement 
contain  free  lime  ?  "  has  been  given,  even  at  the  present  time  ;  the 
influence  of  Fuchs'  theory  has  been  so  strong. 

It  is  also  interesting  to  note  how  the  supporters  of  the  "  free  lime  " 
hypothesis  endeavoured  to  disparage  the  value  of  the  phenolphthalein 
reaction.  Some  of  them  suggested  that  the  "  free  "  lime  in  Portland 
cement  is  in  a  crystalline  state  and  so  is  incapable  of  reaction  as  an 
alkali.  This  suggestion  is  futile,  as  Richter277  has  prepared  crystallised 
lime  and  has  shown  that  in  alcoholic  solution  it  has  an  obvious  alkaline 
reaction. 

Fremy 278  endeavoured  to  show  the  presence  of  free  lime  by  treating 
Portland  cement  with  dilute  acids,  but  Schuljatschenko 279  has  rightly 
shown  that  the  behaviour  of  Portland  cements  towards  dilute  acids  is  a 
most  unsatisfactory  premise  on  which  to  argue  for  the  presence  of  free 
lime,  as  the  whole  of  the  lime  present  can  be  removed  from  the  cements 
by  means  of  dilute  acids. 

Other  investigators  have  used  other  reagents278  *  such  as  Mg(NOs)2. 

*  A  list  of  reagents  which  have  been  tried  for  showing  the  presence  or  absence  of 
free  lime  in  cement  will  be  found  in  the  Bibliography  under  No.  278. 


156  CONSEQUENCES  OF  THE   H.P.   THEORY 

A  considerable  replacement  of  lime  then  occurs,  and  has  been  con- 
sidered to  prove  that  Portland  cement  contains  free  lime.  That  this 
conclusion  is  false  may  be  readily  understood  when  it  is  remembered 
that  such  reagents  are  precisely  those  which  decompose  the  cement. 
Michselis280  has  rightly  shown  that  the  ease  with  which  lime  may  be 
liberated  by  the  action  of  certain  reagents  does  not  prove  that  a 
portion  of  the  lime  in  Portland  cement  is  in  a  weaker  state  of  combina- 
tion. The  statement  made  by  Hardt281,  that  "  feebly  combined  lime  " 
is  the  same  as  "  free  lime,"  is  also  quite  erroneous. 

Nor  does  it  follow  that  soluble  silica  plays  a  special  part  in  the 
hardening  of  cement,  even  though  it  is  true  that  only  those  silicates 
which  contain  "  soluble  silica  "  are  hydraulic.  Erroneous  ideas  as  to 
the  part  played  by  "  soluble  silica  "  occur  throughout  the  literature  of 
cement  ever  since  the  time  of  Fuchs,  and  have,  hitherto,  rendered  it 
impossible  to  evolve  a  sufficiently  comprehensive  theory  of  hydraulites. 
Many  hydraulites,  such  as  plaster,  lime-aluminates,  lime-borates  and 
several  calcium  and  magnesium  oxides,  contain  no  silica  at  all.  Is  it 
not  probable  that  these  silica-free  substances  harden  in  accordance 
with  the  same  general  law  as  the  silicate  cements  ?  Yet  no  one  appears 
to  have  realised  the  possibility  of  the  "  soluble  silica  "  taking  no 
part  whatever  in  the  hardening  process,  for  even  Jordis  and 
Kanter282,  who  regard  all  previous  theories  respecting  the  constitu- 
tion of  cements  as  without  foundation  and  erroneous,  lay  great 
emphasis  on  the  importance  of  "  soluble  silica  "  in  the  hardening  of 
cement. 

The  influence  of  Fuchs'  theory  is  also  shown  by  Heldt283,  who  was 
clearly  of  the  opinion  that  the  value  of  cements  lies  chiefly  in  the  pro- 
portion of  "  soluble  silica  "  they  contain  and  that  the  alumina  is  only 
detrimental,  when  he  wrote  :  "  If  an  aluminosilicate  is  present  in  a 
mortar  (cement)  it  exists  simply  as  a  wholly  inert  material  and  takes 
no  part  in  the  setting  or  hardening,  but  is  harmful  because  it  reduces  the 
proportion  of  silica  present.  Each  per  cent,  of  aluminosilicate  which 
is  not  combined  with  lime  is  lost,  so  far  as  the  formation  of  a  hardening 
compound  is  concerned,  and  remains  as  an  insoluble  and  inert 
material."  It  is  not  surprising  that  Heldt  drew  the  following  curious 
inference  from  this  theory  :  "  If  it  were  possible  to  prepare  a  hydraulic 
mortar  (cement)  containing  23  per  cent,  of  soluble  silica,  all  existing 
cement  works  would  be  ruined,  as  the  best  Portland  cement  only 
contains  15-16  per  cent,  of  soluble  silica,  which  is  reduced,  by  the 
addition  of  water  and  after  hardening,  to  only  7  to  10  per  cent,  in  the 
final  product." 

Chatoney  and  Rivot284 — two  French  investigators — endeavoured 
to  put  Heldt 's  theory  to  practical  use.  Schuljatschenko  has  published 
the  following  comments  on  this  interesting  portion  of  the  history  of 
the  cement  industry:  "Two  writers,  Chatoney  and  Rivot284,  the 
latter  a  learned  chemist  and  professor  at  the  School  of  Mines,  in  their 
treatise  on  materials  employed  in  structural  work  on  the  sea  coast, 


PORTLAND   CEMENT  THEORIES   CRITICISED          157 

reached  the  remarkable  conclusion  that  only  those  cements  are  durable 
in  sea-water  which  consist  of  the  simplest  compounds  such  as  those 
made  of  lime  and  silica.  Roman  cements,  puzzolans  and  other  cements 
lack  durability  in  so  far  as  their  composition  is  complex.  ..."  These 
authors  arranged  that  the  sea  walls  in  the  harbours  of  St.  Malo  and  La 
Rochelle  should  be  built  with  silicates  free  from  alumina,  and  it  is 
easy  to  understand  the  panic  which  occurred  among  French  engineers 
when  they  noticed  the  rapidity  with  which  the  cement  used  at  these 
places  was  destroyed. 

Fuchs'  theory  also  influenced  the  methods  of  investigation  of  the 
constitution  and  hardening  of  Portland  cements.  His  view,  that  the 
hardening  was  due  to  the  formation  of  a  given  calcium  silicate,  led  to 
an  enquiry  as  to  which  substances  were  formed  during  the  hardening 
of  the  cement.  These  substances  were  later  termed  the  "  effective 
substances  "  of  the  cement.  For  over  fifty  years  innumerable  investi- 
gators have  endeavoured  to  find  the  substance  which  is  the  chief  cause 
of  the  hardening  of  cements,*  and  it  is  noteworthy  that  everyone 
who  was  able  to  prepare  an  aluminate  or  silicate  which  possessed  the 
power  of  setting  in  water,  at  once  declared  that  it  was  to  this  substance 
that  Portland  cement  owes  its  setting  power  !  The  result  is  that  there 
are  nearly  as  many  "  effective  substances  "  as  investigators.  All  kinds 
of  calcium  silicates — from  the  mono-  to  the  hexa-silicates — and  many 
calcium  aluminates  have  been  prepared  in  this  connection,  and,  to  add 
to  the  difficulty,  the  silicates  which  one  investigator  declared  to  be 
hydraulic  were  found  by  another  to  have  no  hardening  power.  "  Hence, 
almost  all  possible  calcium  silicates,"  write  Jordis  and  Kanter284b, 
"  have  been  '  found  '  in  cement  clinker  ;  indeed,  some  investigators 
have  not  confined  themselves  within  the  limits  of  the  theoretically 
possible  !  There  is,  in  fact,  a  repletion  of  silicates  calculated  from 
cement  analyses,  the  only  evidence  for  the  existence  of  which  is  that 
the  (assumed)  compositions  of  these  various  silicates,  aluminates, 
ferrates,  etc.,  when  added  together  in  the  proportions  in  which  they 
are  alleged  to  be  present,  agree  with  those  of  Portland  cement. 
Surely  this  is  a  weak  argument  when  it  is  realised  what  is  meant  by 
the  inclusion  of  all  the  possible  combinations  !  " 

Fuchs'  theory  is  also  responsible  for  the  fact  that  no  one  has 
hitherto  regarded  the  Portland  cements  as  chemical  compounds,  as 
this  would  be  in  direct  opposition  to  the  view  that  the  value  of  a 
cement  lies  in  the  (free)  "  soluble  silica  "  present.  It  has,  in  fact,  been 
generally  agreed  that  Portland  cement  is  either  a  mixture  of  various 
compounds  (cf.  the  theories  of  Le  Chatelier 285,  the  Brothers  Newberry 286, 
Kosmann287,  Jex288,  etc.)  or  a  fused  mass  of  indefinable  compounds. 
Erdmenger289  regards  Portland  cement  as  a  "glass";  Hardt290  as  a 
"  solid  solution,"  and  the  theories  propounded  by  Schonaich-Caro- 
lath291,  Schott292,  Zsigmondy293,  Meyer-Mahlstatt294,  Rohland295,  etc., 

*  For  a  list  of  theories  of  hardening  the  reader  should  refer  to  No.  284a  in  the 
Bibliography. 


158  CONSEQUENCES  OF  THE   H.P.  THEORY 

are  of  a  similar  nature.*  These  theories  find  a  merely  superficial 
support  from  the  microscopical  examinations  of  thin  sections  of  clinker 
by  Le  Chatelier296,  Feret,  Tornebohm297  and  others,  who  have  found 
that  commercially  valuable  clinker  may  be  composed  of  several 
different  materials,  f  Tornebohm297  has  suggested  the  terms 
"alite,"  "belite,"  "celite,"  and  "/elite"  for  the  chief  of  these  con- 
stituents. 

This  suggestion — although  at  first  sight  it  appears  to  be  in  support  of 
a  "  mixture  "  theory — is  not  at  all  determinative,  for  no  one  has  yet  been 
able  to  isolate  these  various  constituents  (e.g.  by  means  of  a  mechanical 
analysis),  nor  is  there  any  general  agreement  as  to  the  composition  of 
these  "  constituents."  Thus,  Le  Chatelier  considers  that  the  clinker  is 
chiefly  composed  of  tri-calcium  silicate — a  substance  which  has  not  yet 
been  prepared,  with  certainty,  in  a  crystalline  state,  but  is  a  purely 
hypothetical  one.  Tornebohm,  on  the  contrary,  regards  it  as  a  product 
composed  of  alumina,  silica,  and  calcium. 

If  alite,  belite,  etc.  exist  as  real  constituents  of  cement,  each  having 
a  different  composition,  it  must  be  impossible  to  obtain  cement  clinker 
of  perfect  uniformity.  Yet  Richardson298  has  produced  clinkers  which, 
when  viewed  in  thin  sections,  appear  to  be  completely  homogeneous, 
and  correspond  exactly  to  good  commercial  clinkers.  J 

It  is  very  probable  that  the  want  of  uniformity  observed  by  Le 
Chatelier,  Tornebohm  and  others  in  thin  sections  of  clinker,  is  due  to 
a  crystallographic  and  not  to  chemical  differences  in  the  material. 
This  appears  all  the  more  probable  when  it  is  remembered  that  it  has 
not  yet  been  found  possible  to  isolate  any  definitely  characteristic 
constituents  from  the  clinker  by  means  of  sedimentation  or  mechanical 
analysis.  For  instance,  Schott299  found  that  a  mechanical  separation 
by  means  of  moving  fluid  merely  divided  the  material  into  grains  of 
different  sizes,  the  finest  having  the  same  chemical  composition  as  the 
coarsest. 

[The  preparation  of  transparent  sections  of  cement,  as  mentioned  above,  is  ex- 
tremely difficult  and  is  not  altogether  satisfactory.  It  is  much  better  to  make  a  micro- 
graphic  analysis  of  pieces  of  polished  cement  clinker  etched  with  water  or  1  per  cent, 
hydrochloric  acid  and  viewed  by  reflected  light.  Such  pieces  show  that  the  greater 
part  of  the  cement  is  composed  of  crystals  of  a  single  constituent  ("  alite  "),  separated 
by  a  much  smaller  quantity  of  intercrystalline  material  (celite  ?  with  traces  of  belite  ?). 
Only  the  crystalline  matter  is  of  value,  the  other  being  quite  inert.  The  composition 
of  the  intercrystalline  matter  is  uncertain  ;  it  may  be  the  same  as  that  of  crystals,  the 
material  being  merely  in  a  different  physical  state. 

Pure  "  alite  "  has  been  prepared  by  O.  Schmidt  and  K.  Unger  (Der  Portland 

*  For  further  information  on  the  constitution  of  cement  clinkers  see  No.  295  in 
the  Bibliography. 

t  For  further  information  on  the  microscopical  examination  of  cement  see 
No.  298  in  the  Bibliography. 

J  In  a  critique  of  the  hexite-pentite  theory  made  shortly  after  the  publication  of 
the  German  edition  of  the  present  work,  Allen  and  Shepherd  stated  that  a  reinvestiga- 
tion  of  Richardson's  clinkers  with  improved  appliances  showed  that  they  were  not 
homogeneous.  This  discovery,  which  was  not  known  to  the  authors  when  this  book 
was  written,  does  not  affect  their  argument,  but  only  shows  that  Richardson  was  un- 
able to  produce,  as  he  had  hoped,  a  perfectly  homogeneous  cement.  This  has,  however, 
been  obtained  by  Schmidt  and  Unger,  as  pointed  out  in  the  translator's  note  (below). 


PORTLAND   CEMENT  THEORIES  CRITICISED         159 

Zement,  Stuttgart,  1906,  p.  102)  by  heating  a  mixture  containing  67  per  cent,  of  lime 
to  fusion.     The  "  alite  "  crystals  had  a  composition  corresponding  to  : 

Lime 67.33 

Silica    23.50 

Alumina 3.82 

Iron  oxide  2.28 

Magnesia   2.34 

Other  matter    0.73 


100.00 

According  to  C.  Desch709,  "  These  crystals  are  completely  homogeneous,  so  that 
we  are  fully  justified  in  regarding  them  as  a  solid  solution  of  calcium  silicate  and 
aluminate,  but  not  in  assigning  to  them  a  definite  chemical  formula." 

This  statement  of  Desch's  is  most  peculiar.  Surely  the  fact  that  the  material  is 
crystalline  is  opposed  to  its  being  a  "  solid  solution,"  and  in  any  case  it  is  not  clear 
why  it  is  wrong  to  assign  a  chemical  formula  to  crystals. 

In  criticising  the  German  edition  of  the  present  work,  C.  Desch  complains  that  the 
authors  have  not  paid  sufficient  attention  to  the  structure  of  cements  as  revealed  by 
the  microscope.  Yet  this  investigator,  whilst  accepting  the  homogeneity  of  Schmidt 
and  Unger's  cement,  refuses  to  regard  it  as  a  definite  chemical  compound  !  The  "  solid 
solution  "  theory,  which  he  prefers,  has  been  exhaustively  discussed  in  the  general 
criticism  of  the  various  theories  respecting  silicates  (p.  13)  and  is  further  confuted  by 
the  fact  that  no  Portland  cement  has  yet  been  found  which  does  not  conform  to  the 
hexite-pentite  theory,  which  states  that  such  cements  are  highly  basic  calcium  salts  of 
aluminosilicic  acids.  Besides,  the  properties  of  Portland  cement  do  not  coincide  with 
Desch's  or  any  other  theory  of  mixed  crystals.  (Vide  pp.  13,  22  and  162.)  In  short, 
there  can  be  no  single  substance  forming  the  essential  constituent  of  all  Portland  cements 
and  corresponding  to  alite,  because,  as  the  authors'  formulae  show,  the  compositions 
of  cements  differ  greatly  from  each  other,  although  they  all  admittedly  fall  within  certain 
limits  when  expressed  in  the  form  of  an  ultimate  analysis.] 

There  is  a  sense  in  which  all  theories  published  on  the  silicate 
cements  are  developments  of  that  of  Fuchs,  and  a  considerable  number 
of  investigators  at  the  present  time  are  still  under  its  influence.  It  is, 
however,  impossible  to  find  that  these  theories  have  led  to  any  satis- 
factory results,  but  rather  to  the  opposite.  The  worthlessness  of 
these  theories  is  particularly  noticeable  when  an  attempt  is  made  to 
use  them  in  explaining  the  various  experimental  results  which  have 
been  obtained  in  silicate  cements.  Thus,  in  the  light  of  the  foregoing 
theories,  the  following  facts  are  inexplicable  : 

(a)  It  is  known  that  the  best  temperature  for  burning  a  mixture 
of  clay  and  lime  or  chalk  in  the  production  of  Portland  cement  is  the 
temperature  at  which  the  amount  of  vitrification  is  readily  appreciable 
to  the  unaided  eye  *  and  that  the  quality  of  the  cement  also  depends 
on  the  duration  of  the  heating.  If  this  is  too  prolonged  or  the  tempera- 
ture is  too  high,  a  cement  of  lesser,  or  of  insignificant  value  is  produced. 

The  theories  previously  mentioned  afford  no  explanation  of  this 
important  fact. 

(6)  Silica  cements  which  have  been  heated  to  the  sintering  point, 
become  gelatinous  when  treated  with  dilute  acids. 

This  fact  is  well  known,  but  not  the  slightest  explanation  has  yet 
been  given  as  to  its  cause. 

*  This  is  sometimes  termed  the  "  sintering  point."  It  is  reached  when  sufficient 
fusion  has  occurred  to  render  the  mass  impervious  to  any  suitable  fluid  which  has  no 
chemical  action  on  the  material. — A.  B.  S. 


160  CONSEQUENCES   OF  THE   H.P.   THEORY 

(c)  It  is  known  that  in  Portland  cements  a  portion  of  the  lime  is 
more  readily  removable  than  the  remainder.    The  usual  explanations 
offered  are  that  cements  contain  both  free  and  combined  lime,  or  that 
part  of  the  lime  is  in  a  state  of  weaker  combination  than  the  rest.    The 
first  or  "  free  lime  "  hypothesis  has  been  shown  in  previous  pages  to  be 
opposed  to  the  facts.    The  second  is  often  thought  to  be  supported  by 
the  supposed  presence  of  highly  basic  silicates  and  aluminates  in  the 
cement.   The  behaviour  of  Portland  cement  towards  certain  reagents  is, 
however,  opposed  to  this  hypothesis.    The  supposition  that  calcium 
silicates  are  present  is  founded  on  Winkler's  experiments,  which  showed 
the  calcium  silicates  to  be  insoluble  in  an  alcoholic  solution  of  hydro- 
chloric acid.    From  this  it  was  argued  that  those  portions  of  cement 
which  are  insoluble  in  this  reagent  are  composed  of  calcium  silicate. 
Calcium  aluminates  react  alkaline  to  an  alcoholic  solution  of  phenol- 
phthalem.    Portland  cements  should,  therefore,  produce  a  red  colour 
with  this  reagent.    As  a  matter  of  fact,  they  do  not  do  so. 

Hence,  the  ready  separation  of  a  definite  proportion  of  lime  from 
Portland  cements  is  very  puzzling  in  the  light  of  previous  theories. 

(d)  By  granulating  furnace  slags  it  has  been  found  possible  to 
produce  silicate  cements  which  will  only  set  or  harden  in  the  presence 
of  water  containing  lime  or  other  alkalies  in  solution.    None  of  the 
theories  previously  mentioned  can  be  used  to  explain  this  fact.    Ac- 
cording to  Zulkowski300  some  Portland  cements,  as  soon  as  they  have 
lost  a  certain  percentage  of  lime,  possess  this  characteristic  of  slag 
cements  and  will  only  harden  in  the  presence  of  alkaline  fluids  and  not 
at  all  with  water  alone.    None  of  the  existent  theories  show  any  genetic 
relationship  between  the  Portland  cements  and  the  slag  cements. 

As  a  matter  of  fact,  there  is  such  a  relationship,  as  will  be  shown  later. 

(e)  Lunge's301  investigations  on  the  resistance  to  alkalies  of  granu- 
lated and  ungranulated  slags  showed  that,  in  the  latter,  the  aluminium 
is  more  strongly  combined  than  in  the  former.    There  is  no  explanation 
of  this  fact  outside  the  present  volume. 

(/)  The  existing  theories  neither  permit  the  prediction  of  the 
following  facts,  nor  do  they  provide  a  satisfactory  explanation  of  them  : 

(1)  According  to  Schott  302  a  considerable  proportion  of  lime  may  be 
removed  from  a  cement  without  affecting  its  setting  and  hardening  power. 

(2)  According  to  Michaelis303,  Schott,  and  others,  it  is  possible  to 
reproduce  the  original  cement  from  one  which  has  been  fully  hardened. 

(3)  If  a  cement  is  allowed  to  set  and  is  then  ground  to  powder  and 
again  mixed  with  water,  it  will  again  set  hard,  but  not  so  strong  as  before. 

(g)  There  can  be  scarcely  any  doubt  that  hardened  cements  are 
very  sensitive  to  certain  salts,  particularly  to  sulphates.  None  of 
the  existing  theories  can  explain  this  harmful  action  of  sulphates,  nor 
do  they  indicate  any  means  whereby  it  may  be  avoided.  When  it  is 
remembered  that  an  explanation  of  the  harmful  action  of  sulphates  on 
cement  is  probably  the  most  likely  means  of  overcoming  the  difficulties 
caused  by  these  compounds — including  the  possible  solution  of  the  sea- 


PORTLAND   CEMENT  THEORIES   CRITICISED         161 

water  problem — it  is  not  difficult  to  imagine  that  the  inability  of 
existing  theories  to  throw  any  light  on  this  important  subject  is  one  of 
the  gravest  objections  to  their  use.  Another  special  weakness  of 
existing  theories  lies  in  the  assumption  made  in  almost  all  of  them, 
that  Portland  cements  are  not  single  compounds.  This  assumption, 
which  is  entirely  without  foundation  in  fact,  not  only  limits  the  develop- 
ment of  chemical  knowledge  of  the  silicate  cements,  but  makes  such 
development  quite  impossible. 

The  opinion  that  Portland  cements  do  not  form  chemical  in- 
dividuals is  doubtless  due  to  the  prevalent  ideas  of  the  constitution  of 
the  substances  from  which  these  cements  are  derived,  viz.  the  clays. 
The  conception  of  other  derivatives  of  clay,  such  as  the  ultramarines,  as 
chemical  individuals  is  also  made  difficult  for  the  same  reason. 

Now  that  it  has  been  shown  (a)  that  the  clays  and  ultramarines  may 
be  regarded  as  true  chemical  individuals  (i.e.  as  definite  chemical 
compounds),  (b)  that  by  so  regarding  them,  the  whole  mass  of  pub- 
lished experiments  on  the  silicates  becomes  explicable,  and  (c)  that  this 
conception  of  them  has  the  characteristics  of  a  true  chemical  theory — 
one  which  permits  a  single  classification  for  all  these  substances  as  well 
as  the  deductive  study  of  them — it  appears  to  be  highly  probable  that 
the  Portland  cements,  which  are  nothing  more  than  derivatives  of 
claj^s,  may  also  be  regarded  as  chemical  individuals,  provided  that 
no  facts  are  opposed  to  this  view. 

When  it  is  added  that  by  thus  regarding  the  Portland  cements  as 
definite  chemical  individuals  and  applying  the  new  hexite-pentite 
theory  to  them,  the  meaning  of  the  whole  mass  of  published  experi- 
mental results  becomes  clear  and  that  a  new  means  of  solving  the 
important  "  sea-water  "  problem  is  provided,  it  is  hardly  too  much  to 
suppose  that  there  will  scarcely  be  a  chemist  who  will  continue  to 
regard  Portland  cements  in  the  old  erroneous  manner  as  mixtures  of 
various  substances. 

In  applying  the  new  theory  to  Portland  cements,  the  following 
subjects  must  be  considered  : 

(a)  The  chemical  constitution  of  the  Portland  cements. 

(b)  The  reactions  which  occur  during  the  formation  of  Portland 
cements,  and  the  influence  of  the  duration  of  heating  and  of  the 
temperature  on  the  products. 

(c)  A  new  theory  of  setting  and  hardening. 

At  the  suggestion  of  A.  B.  Searle  the  following  statements,  which 
occur  in  various  text-books,  are  dealt  with  more  specifically  than  in  the 
original  (German)  edition  of  this  treatise  : 

(a)  The  temperature  in  a  cement  kiln  only  effects  a  partial  fusion  of  the  material. 
(6)  Chemical  reactions  between  solid  substances  take  place  very  slowly  and  are 
seldom  complete. 

(c)  Cement  clinker  is  not  a  homogeneous  substance,  but  merely  a  mixture  or  a 
solid  solution,  and  correct  conclusions  as  to  its  chemical  constitution  cannot  be  drawn 
without  studying  each  of  the  constituents  separately. 

(d)  The  chemical  reactions  which  occur  in  the  burning  of  cement  are  never  com- 
plete, and  it  is  therefore  incorrect  to  regard  the  product  as  a  single  compound,  the 
constituents  of  which  are  in  proportions  conformable  to  the  laws  of  Dalton  and  Proust. 

M 


162  CONSEQUENCES   OF  THE   H.R  THEORY 

(e)  Cement  clinker  consists  essentially  of  colloidal  substances  and  the  properties 
of  cement  are  due  to  the  colloidal  nature  of  its  various  constituents. 

With  respect  to  (a),  a  partial  fusion  of  the  material  is  not  incom- 
patible with  the  unitary  nature  of  the  clinker,  i.e.  it  does  not  neces- 
sarily imply  that  clinker  is  not  composed  of  a  single  definite  compound. 
The  partiality  of  the  fusion  is  due  to  the  low  heat  conductivity  of  the 
material,  whereby  the  melting  point  is  not  reached  in  the  interior  of 
the  mass. 

[An  interesting  parallel  to  this  was  found  by  J.  W.  Cobb,  who  showed  that  lime 
and  silica  enter  into  complete  combination  even  though  the  temperature  reached  is  far 
below  that  required  to  fuse  the  lime  and  silica  or  the  compound  so  formed.] 

The  statement  (b),  that  the  chemical  reactions  between  solid 
materials  are  slow  and  seldom  complete,  is  by  no  means  true  at  high 
temperatures.  Besides,  there  is  no  positive  proof  that  on  heating  a 
mixture  of  kaolin  with  calcium  carbonate  (the  pure  constituents  of  a 
raw  cement  mix)  the  clinker  contains  free  clay  as  well  as  free  calcium 
carbonate  or  rather  free  lime.  On  the  contrary,  the  very  small  pro- 
portion of  insoluble  matter  in  cement  clinker  (only  1-2%)  shows  that 
the  reaction  is  remarkably  complete. 

[Cobb's  experiments,  mentioned  above,  afford  a  further  proof  of  the  speed  and 
completeness  of  reactions  between  solid  substances.] 

That,  as  stated  in  (c),  clinker  is  a  mixture  and  not  a  compound  is 
purely  an  assumption  and  not  a  fact.  Of  the  two  assumptions,  (1)  that 
cement  clinker  is  a  compound,  and  (2)  that  it  is  a  mixture,  that  must 
be  the  more  probable  which  satisfies  the  most  facts  and  enables  the 
prediction  of  the  most  properties  to  be  made.  This  is  unquestionably 
true  of  the  assumption  that  cement  clinker  is  a  true  chemical  com- 
pound. 

Statement  (d)  is  sufficiently  answered  in  the  comment  on  statement 
(b)  given  above. 

Statement  (e)  that  cement  clinker  is  essentially  colloidal  is  another 
pure  assumption  which  is  quite  unnecessary.  It  is  true  that  cements 
have  some  characteristics  in  common  with  colloids,  especially  with 
regard  to  their  behaviour  on  treatment  with  water.  Any  confusion 
which  may  arise  in  this  connection  can  only  be  due  to  a  superficial 
appreciation  of  the  properties  and  structure  of  colloids.  For,  as  a 
matter  of  fact,  the  colloidal  properties  of  cements  and  clays  are  by  no 
means  incompatible  with  their  chemical  individuality,  and,  in  the 
authors'  opinion,  the  colloids  themselves  are  not  mixtures,  but  definite 
chemical  compounds  of  very  high  molecular  weight. 

It  is  most  surprising  that  C.  Desch,  on  the  one  side,  and  E.  T.  Allen 
and  E.  S.  Shepherd,  on  the  other,  in  their  reviews  of  the  German 
edition  of  this  work  reproached  the  authors  of  the  H.P.  theory  for 
regarding  Portland  cements  as  definite  chemical  compounds  and  not  as 
mixtures.  These  critics  believe  that  the  microscopical  investigation  of 
cements  has  shown  positively  that  cements  are  heterogeneous  sub- 
stances. This  is  the  sole  argument  which  has  been  brought  in  opposi- 
tion to  the  H.P.  theory. 

Unfortunately,  these  critics  have  omitted  to  bear  a  very  important 


PORTLAND   CEMENT   THEORIES   CRITICISED 


16$ 


fact  in  mind,  namely,  that  a  difference  in  crystal  form  does  not  neces- 
sarily prove  the  presence  of  substances  of  different  chemical  composi- 
tion. There  is  always  a  great  probability  of  di-  or  poly-morphism, 
whereby  one  and  the  same  substance  may  assume  different  forms. 

[The  various  forms  which  sulphur  assumes  is  a  particularly  interesting  example  of 
polymorphism  brought  about  by  cooling  under  different  conditions.] 

A  proof  of  the  non-identity  of  the  various  crystalline  substances  in 
cement  can  only  be  furnished  by  proving  that  each  of  them  has  a 
different  chemical  composition.  This  proof — simple  as  it  appears  to  be 
— is  entirely  wanting  with  regard  to  Portland  cements,  and  all  attempts 
which  have  so  far  been  made  to  separate  the  various  crystalline  con- 
stituents have  proved  abortive. 

These  critics  appear  to  adhere  to  one  of  the  numerous  mixture 
theories  of  the  constitution  of  cements,  and  it  would  be  of  great  interest 
if  they  would  only  state  which  is  the  one  they  prefer.  If  it  were  correct 
to  speak  of  a  "  fog  of  theories  "  such  a  term  might  well  be  applied  to 
the  various  mixture  theories  applied  to  Portland  cements.  Jordis  and 
Kanter,  in  their  well-known  work  on  cements,  have  stated  that  all 
kinds  of  compounds,  of  possible  and  impossible  theoretical  constitution, 
may  be  present  as  essential  constituents,  and  when  enquiry  is  made 
as  to  what  the  various  theories  explain,  it  is  almost  impossible  to  find 
a  simple  answer.  The  following  lines  will  give  the  reader  a  clearer  idea 
as  to  the  nature  of  the  mixture  theories  : 

Some  writers  state  the  composition  of  only  a  limited  number  of 
constituents  ;  others  give  the  composition  of  the  clinker.  In  the 
former  class  are  Jex,  Le  Chatelier,  Erdmenger,  Rebuff  at,  Zulkowski, 
etc. ;  in  the  latter  are  Kosmann,  Newberry,  Jex,  etc. 

The  constituents  of  cement  clinker  according  to  the  writers  named 
below  are  shown  in  the  following  Table  : 


Alleged 
Constituent 


Year 


Authority  Quoted  and  Reference 


Si02 
2  CaO  •  SiO5 


3  CaO  •  SiO, 


2-3  CaO  •  SiO2 . 

3-4  CaO  •  SiO2 . 
5  CaO  •  2  SiO2  . 


1884 
1900 
1893 
1899 
1901 
1901 

1856 
1885 
1885 
1901 

1901 
1902 
1902 
1903 

1856 
1865 


Le  Chatelier,  Bull  de  la  Soc.  Chim.,  41,  377. 

Jex,  Tonind.  Ztg.,  1900,  1856. 

Erdmenger,  Chem.  Ztg.,  1893,  982. 

Rebuffat,  Gaz.  Chim.  ital.,  28,  II. 

Zulkowski,  Chem.  Industr.  1901,  290,  and  Pamphlet,  1901. 

Leduc,  Sur  la  dissociation  des  produits  hydrauliquea,  Sept., 

1901. 

Rivot  &  Chatoney,  Comptes  rend,  153,  302,  and  785. 
Le  Chatelier,  Bull,  de  la  Soc.  Chim.,  42,  82. 
Spencer  &  Newberry,  Tonind.  Ztg.,  1898,  879. 
A.  Meyer,  Bull.  Boucarest,  1901,  No.  6;  Tonind.  Ztg.,  1902, 

p.  1895. 

Ludwig,  Tonind.  Ztg.,  1901,  p.  2084. 
Kosmann,  Tonind.  Ztg.,  1902,  p.  1895. 
Clifford  Richardson,  Tonind.  Ztg.,  1902,  p.  1928. 
Michaelis,    Versammlung  des    Vereins  der  Portland  Zement 

fabrikanten,  1903. 

Winkler,  Jour.  f.  prakt.  Chemie,  67,  444. 
Heldt,  Jour.  f.  prakt.  Chemie,  94,  202-37. 


164  CONSEQUENCES   OF  THE   H.P.   THEORY 

The  true  composition  of  clinker  is,  according  to  Kosman  (1895)  : 

4r\n    CJi/"^        I      )  ^-^2  *  -*^*2^-)  *  ^4  ( 
Ca2biO4  +  I  £a2  f  g.^         4  | , 

According  to  Newberry  (1898)  : 

x  (3  CaO  •  SiO2)  +  y  (2  CaO  •  A1203). 
According  to  Jex  (1900)  : 

h  c(CaSi03) 


ICaO 


CaO 
CaO 


2  CaO 
and  according  to  Ludwig  (1901)  : 

3.033  CaO  -f  0.125  MeO  +  0.217  A1203  +  1  Si02, 
or  3.158  MeO  +  0.217  A1203  -f  1  Si02. 

The  published  opinions  as  to  the  chemical  composition  of  hardened 
cements  and  of  the  constituents  which  cause  this  hardening  are 
equally  divergent  and  confusing,  as  the  examples  in  the  following 
Table  will  show  : 

Alleged  Constituents  Causing  the  Hardening  of  Cements 


Alleged 
Constituent 


Authority  Quoted  and  Reference 


CaO  •  Si02  •  HaO 

4  CaO  •  3  Si02  •  H2O 

5  CaO  •  3  SiOa  •  H2O 
3  CaO  •  2  Si02  -  H2O 

2  CaO  •  SiO2  •  H2O 

3  CaO  •  SiO2  •  H2O 


Le  Chatelier,  Bull,  de  la  Soc.  Chim.,  1885,  42,  82. 

Jex,  Tonind.  Ztg.,  1900,  1856-1919. 

A.  Meyer,  Bull.  Boucarest,  1901,  No.  6. 

Zulkowski,  Pamphlet,  1901. 

Landrin,  Compt.  rend.,  1883,  96,  156,  379,  841,  1229. 

Michaelis,  Jour.  f.  prakt.  Chemie.,  1867,  100,  257-303. 

Michaelis,  Verhandlung  d.  Vereins  z.  Beford.  d.  Gewerbefleizes,  1896, 

317. 

Rebuffat,  Tonind.  Ztg.,  1899,  782,  823,  853,  1900. 
A.  Meyer,  Butt.  Boucarest,  1901,  No.  6. 
Erdmenger,  Chem.  Ztg.,  1893,  982. 
Rivot  &  Chatoney,  Compt.  rend.,  1856,  153,  302,  785. 
Michaelis,  Jour,  prakt.  Chemie.,  1867,  100,  257-303. 


Michselis  has  also  stated  that  the  composition  of  a  fully  hardened 
cement  may  be  represented  by  : 

246  (3  CaO  •  R203+3  H20)+661  (5  CaO  •  3  Si02+5  H20)+93  (CaO-J-H20). 

Allen  and  Shepherd  have  made  the  remarkable  statement  that  the 
view  that  Portland  cement  is  a  mixture  of  various  constituents  is 
supported  by '  a  large  amount  of  evidence.'  It  would  be  mostinteresting 
to  see  this  voluminous  evidence,  as  it  is  entirely  unknown  to  the  authors 
of  the  H.P.  theory.  Indeed,  these  critics  appear  to  have  overlooked 


THE  CONSTITUTION   OF  PORTLAND   CEMENTS       165 

a  fact  to  which  Rohland  has  drawn  attention,  namely,  the  undeniable 
relationship  between  the  constitution  of  clays,  ultramarines  and 
Portland  cements.  If  Portland  cements  were  mixtures,  then  clays 
and  ultramarines  could  not  be  definite  chemical  compounds,  yet  the 
available  experimental  evidence  is  entirely  in  support  of  their  definite 
chemical  composition. 

Almost  all  students  of  the  constitution  of  Portland  cements  have 
overlooked  the  following  considerations  : 

Portland  cements  are,  theoretically,  highly  basic  lime  salts  of 
aluminosilicic  acids,  i.e.  they  are  basic  salts  of  which  clays  are  the 
corresponding  acids.  Their  general  properties  are  in  entire  agreement 
with  this  view  of  their  constitution,  and  it  is  incomprehensible  that  on 
treating  clay  with  calcium  carbonate  in  the  manufacture  of  cement, 
the  product  should  not  be  a  lime  salt,  but  a  mixture  of  various  silicates 
and  alurninates.  It  must  also  be  remembered  that  Vernadsky  has 
proved  that  free  carbon  dioxide  is  evolved  when  kaolin  is  heated  with 
sodium  carbonate  and  that  a  sodium  salt  is  formed  quantitatively. 
Analogous  reactions  occur  in  the  synthesis  of  ultramarine  from  clay, 
sodium  carbonate  and  sulphur,  wherein  sulphur  addition-products  of 
the  sodium  salt  of  the  clay  are  formed.  There  is  no  foundation  whatever 
for  the  assumption  that  the  reaction  between  calcium  carbonate  and 
clay  produces  any  other  substances  than  those  which  the  H.P.  theory 
demands. 

(a)  The  Chemical  Constitution  of  the  Portland  Cements 
If  any  suitable  hydro-aluminosilicate  such  as 

_AAAA, 

Si  I  Al  I  Al  I  Si 


H20(Si  -  Al  -  Al  •  Si), 

— which  has  been  repeatedly  mentioned  on  previous  pages — be  exam- 
ined, it  will  be  found  (p.  139)  to  possess  two  kinds  of  OH-groups,  viz. 
a-  and  s-hydroxyls.  The  a-hydroxyls  play  a  special  part  in  the  forma- 
tion of  the  ^4-aluminosilicates ;  in  the  formation  of  Portland  cements 
the  s-hydroxyls  are  specially  important.  The  hydrogen  of  the 
5-hydroxyls — which  may  be  briefly  referred  to  as  ^-hydrogen — is,  unlike 
the  a-hydrogen  of  the  a-hydroxyls,  replaceable  by  such  groups  as  : 

— R"-OH,     — R"-O-R"-OH    and    — R"  •  O  •  R"  •  O  •  R"  •  OH, 

(R"  =  Ba,  Sr,  Ca,  Mg,  etc.) 

The  basic  atomic  complexes  are  known  as  hydro-basic  groups  and  as 
side-chains.*   If  the  elements  of  water  are  split  off  from  two  neighbour- 

*  For  an  explanation  of  side-chains    a  good  text-book   on   organic   chemistry 
should  be  consulted. — A.  B.  S. 


166 


CONSEQUENCES  OF  THE   H.P.   THEORY 


ing  (ortho)  positions  in  the  hydrobasic  side-chains,  anhydrobasic  groups 
are  formed  as  shown  : 

-0-R''-|OH 
—0  •  R"  •  OlH 


—0  •  R" 
—  0  •  R" 


O  •  R 


—0  •  R\ 

/o 

—  0  •  R"x 

O  •  R" 

^ 

0  •  R"  • 

O  •  R"/° 

The  hydrobasic  atomic  complexes 

— 0  •  R"  •  OH,  —  0  •  R"  •  O  •  R"  •  OH  and  — 0  •  R"  •  0  •  R"  •  0  •  R"  •  OH 
may  be  represented,  according  to  the  number  of  R"-atoms,  by 

(1),  (2)  and  (3), 
respectively,  and  the  anhydrobasic  complexes 

—0  •  R"\        —0  •  R" \        — 0  •  R"  •  0  •  R^ 

__ o  •  R"/0'    — O  -  R"  -  O  -  R"/0'     — O  •  R7'  •  0  •  R"' 

— O  •  R"  •  O  •  R" \        —  O  •  R"  •  O  •  R*  •  O  •  R"\n 

R"  -  O  •  R"  •  O  •  R"/0'     — 0  •  R"  •  0  •  R"  •  O  •  R"/° 


etc., 


O  •  R  V 
may  each  be  indicated,  according  to  the  number  of  R  "-atoms,  by 

2°,  3°,  4°,  5°,  6°,  etc. 
A  few  examples  will  make  this  clear  : 


2  K2O  •  28  R"O  •  6  H2O  • 

6  A1203  •  12  Si02 

Hydrobasic  Salt. 


Na2O  •  20  R"O  •  6  H20  • 

H20  •  6  A1203  •  12  Si02 

Hydrobasic  Salt. 


4  H20  •  40  R"0  •  6  A1203  •  12  Si02 

Hydro-anhydrobasic  Salt. 


3°= 


3°== 


28  R"0  •  6  A1203  •  12  Si02 
Anhydrobasic  Salt. 


THE   CONSTITUTION   OF   PORTLAND   CEMENTS       167 

What  has  been  stated  with  regard  to  substances  of  the  type 

Si  •  Al  •  Al  •  Si  is  equally  applicable  to  other  types,  and  the  existence 
is,  therefore,  possible  of  : 


3°= 


4°  4° 

- f'YA 

Si  |Al|Sij>=3° 

11      \/      II 
4°  4° 


etc.  etc. 


The  Al  may  be  partially  or  completely  replaced  by  the  sesquioxides 
Fe"',  Cr'",  Mn'",  Ce"',  etc.,  and  the  Si  by  Sn,  Ti,  Zr,  etc.,  whereby  the 
number  of  these  basic  salts  is  largely  increased. 

Some  of  these  basic  salts  with  definite  hydro-  or  anhydro-basic  side- 
chains  (viz.  when  R"=Ca,  Mg)  are  manufactured  on  a  large  scale  and 
are  sold  commercially  in  a  finely-powdered  state  under  the  name  of 
"  Portland  Cement."  (It  would  be  more  correct  to  use  the  plural  form 
— "  Portland  Cements.") 

These  Portland  cements  certainly  contain  3°  chains  ;  their  maxi- 
mum content  of  base  remains  to  be  found.  Good  samples  appear  never 
to  exceed  a  maximum  corresponding  to  6°  side-chains.  Apart  from 
this,  these  cements  appear  to  contain  a  little  alkali  (in  the  aluminium 
hexite),  a  little  water  (probably  basic),  and  small  quantities  of  such  salts 
as  K2S04,  K2CO3,  Na2SO4,  CaSO4,  etc.,  but  only  as  impurities. 

The  following  are  typical  examples  of  Portland  cements  : 

(2)(2)      OK     OK  (2)(2) 

II          I          I          II 


4°= 


4°= 


= 4C 


+  0.5  CaSO«  +  0.5  Na(K)CO, 


4°       ONa  ONa    4° 
2  H20  •  24  CaO  •  8  MgO  •  K20  •  Na20  •  6  A1203  •  12  Si02+2. 

5°   OK  5° 


Si 


Al    Si 


+  0.5  NaCl 


20  CaO  •  16  MgO  •  K20  •  3  A1203  •  12  Si02  +  0.5  NaCl. 


'\/\/\/' 


168  CONSEQUENCES   OF  THE   H.P.   THEORY 


+  0.5  K2S04 


5° 
39  CaO  •  3  A1203  •  15  Si02  +  0.5  K2S04,  etc.  etc. 

(b)  The  Reactions  occurring  in  the  formation  of  Portland  Cements,  and  the 
influence  of  the  time  of  heating  and  the  temperature  on  the  Products 

Portland  cements  may  be  made  by  burning  the  most  widely  different 
clays  with  definite  quantities  of  lime  or  calcium  carbonate.  The  ratio 
of  lime  to  clay  naturally  varies  with  the  latter.  Hitherto,  the  proportion 
of  lime  and  clay  has  been  fixed  empirically,  i.e.  it  has  been  arranged 
according  to  a  definite  rule  (termed  the  hydraulic  modulus)  for  each  kind 
of  clay. 

As,  according  to  the  authors'  theory  (p.  102),  the  clays  are  merely 
aluminosilicic  acids,  the  reactions  which  occur  in  the  burning  of 
cement  are  obvious,  and  consist  chiefly  in  replacing  the  s-hydrogen  in 
the  clay  by  anhydrobasic  groups.  This  cannot  be  so  readily  observed 
in  the  commercial  manufacture  of  these  cements,  as  silica,  alumina, 
lime,  alkali,  etc.  (in  the  form  of  impurities  in  the  coal),  are  added  to  the 
materials  in  the  original  mixture  and  produce  other  types  than  those 
here  described  in  detail. 

To  obtain  some  idea  of  the  influence  of  the  temperature  and  dura- 
tion of  the  heating  it  is  necessary  to  use  the  dynamisation  theory 
(p.  108).  According  to  this,  the  oxygen  valencies  which  are  in  a  satur- 
ated state  in  the  raw  material  are  set  free  when  the  clay,  etc.  is  heated 
to  its  vitrification  point.  If  the  heating  is  prolonged  or  the  temperature 
rises  much  above  that  needed  to  produce  vitrification,  polymerisation 
products  are  formed  and  the  free  oxygen  valencies  again  become 
partially  or  completely  bound.  If  the  heating  is  still  further  prolonged 
or  the  temperature  is  raised  until  the  material  melts,  an  increase  in  the 
density  of  the  basic  silicates  present  may  be  observed.  At  the  melting 
point  of  the  material,  the  polymerisation  attains  a  maximum  ;  the 
maximum  density  must,  of  necessity,  be  reached  simultaneously. 
This  change  in  density  under  the  influence  of  heat  has  been  repeatedly 
observed  by  various  investigators  as  well  as  by  the  authors  of  the 
present  volume. 

From  these  considerations  it  follows  that  the  activity  of  the  basic 
salts  (which  is  due  to  the  liberation  of  secondary  oxygen  valencies  at 
the  vitrification  temperature  of  the  material)  is  diminished  or  even 
destroyed  on  prolonged  heating  at  a  temperature  approaching  the 
melting  point.  303a 


THE   CONSTITUTION   OF  SLAGS  169 

Both  consequences  of  the  theory — (a)  the  increase  in  density  on 
prolonged  heating,  attaining  of  a  maximum  at  the  melting  point,  and 
(b)  the  diminution  of  activity  or  ability  to  hydrate — are  fully  con- 
firmed by  the  facts. 

In  confirmation  of  the  second  consequence  of  the  theory,  the 
following  facts  may  be  cited  :  A  properly  burned  cement,  if  crushed 
to  powder  and  then  mixed  with  a  suitable  proportion  of  water,  readily 
hydrates  at  the  ordinary  temperature.  This  property  of  cement 
diminishes  on  prolonged  heating  at  the  vitrification  point  and,  in  some 
cases,  ceases  entirely  when  the  cement  is  fused. 

If  the  temperature  is  raised  much  above  the  melting  point,  further 
reactions  may  occur,  the  polymerised  molecule  breaking  up  into  its 
original  constituents — i.e.  into  single  cement  molecules — or  decom- 
position occurs  within  the  cement  molecule  itself.  In  the  former  case, 
useful  cements  are  produced.  Schmidt  and  linger  have  prepared 
crystalline  Portland  cements  from  such  fused  substances  by  means 
of  the  electric  arc.  Sauer  has  investigated  the  optical  properties  of 
these  crystals.  When  crushed  and  mixed  with  water  they  set  rapidly, 
with  an  appreciable  development  of  heat. 

This  theory  of  the  formation  of  polymerisation  products  of  alumino- 
silicates  (including  calcium  aluminosilicates)  at  high  temperatures, 
provides  a  simple  explanation  of  several  facts  wilich  have  hitherto 
proved  puzzling.  Among  several  others  : 

The  Eeactions  which  occur  on  granulating  furnace  slags  and  the 
formation  of  Silicate  Cements  from  them303b 

are  thereby  explained. 

The  raw  materials  from  which  iron  is  obtained  are  the  iron  ores. 
In  addition  to  iron,  these  contain  other  earthy  constituents  such  as 
lime,  silica  and  alumina.  The  object  of  smelting  these  ores  with  coke 
in  furnaces  is  to  separate  the  metallic  iron  from  the  other  materials 
and  to  remove  the  latter  in  a  fluid  state  as  slags.  In  order  that  the 
slags  may  possess  the  necessary  fluidity,  the  lime  must  bear  a  certain 
ratio  to  the  silica  and  the  alumina,  and  great  care  is  exercised  by 
iron-smelters  to  ensure  that  this  ratio  is  maintained.  In  most  cases, 
the  proportion  of  lime  in  the  raw  iron  ores  is  too  low  and  an  addition  of 
limestone  is,  therefore,  made.  Under  favourable  conditions,  the 
molten  iron  and  slag  separate  readily  in  the  furnace  on  account  of 
the  great  difference  in  their  specific  gravities,  and  are  allowed  to  flow 
separately  out  of  the  furnace  at  two  different  levels.  The  slag  carries 
off  all  the  lime,  silica  and  alumina  in  the  form  of  a  calcium  alumino- 
silicate. 

If  the  slag  is  "  quenched,"  by  allowing  it  to  fall  into  cold  water,  a 
material  is  obtained  which,  if  crushed  to  a  fine  powder  and  mixed  with 
alkaline  solutions  (lime-water,  etc.),  hardens  to  a  strong  mass.  The 
material  which  has  not  been  granulated  does  not  possess  this  property. 

The  simplest  explanation  for  this  difference  in  behaviour  between 


170  CONSEQUENCES  OF  THE   H.P.   THEORY 

slags  which  have  been  granulated  and  others  is  that  the  latter  are 
polymerised,  whereas  the  quenched  or  granulated  slags  undergo  an 
"  entpolymerisation,"  i.e.  a  breaking  up  into  single  cement  molecules. 

Against  this  view  it  may  be  argued  that  these  slags  are  only 
mixtures  and  not  chemical  compounds,  but  no  satisfactory  proof  has 
been  found  in  support  of  this  objection.  On  the  contrary,  it  is  obvious 
that  the  manner  in  which  these  slags  are  produced  is  neither  irregular 
nor  capricious,  but  is  in  accordance  with  definite  "  laws,"  their  com- 
position only  varying  in  the  several  works  because  of  differences  in 
the  iron  ores  used. 

Hence,  if  an  iron  ore  of  constant  composition  is  used  in  a  given 
works,  the  composition  of  the  slags  will  also  be  constant.  This  conse- 
quence of  the  authors'  new  theory  of  the  constitution  of  slags  is  adopted 
by  Jantzen304,  who  supports  it  by  the  following  analyses  of  furnace 
slags  from  the  Buderus  Iron  Works  in  1888  to  1890,  1893,  1895  and 
1899  : 

Si02        AljO,      F,0,       FeO      MnO  CaO  CaSO4  CaS  MgO  Alkalies 

1888-90     35.20     10.02     0.21     0.55     0.30  47.10  1.56  2.17  1.20  (not  determined) 

1893       34.50     10.90     0.18     0.64     0.46  47.44  1.44  1.99  1.36     „ 

1895       34.23     10.28     0.33     0.64  Trace  48.26  1.87  2.07  1.13     „ 

1899       35.40     10.45     v , '     0.37  46.74  1.72  1.81  1.20     „ 

0.91 

This  remarkable  regularity  in  the  composition  of  the  slags  during 
so  long  a  period  cannot  be  a  mere  coincidence.  It  is  far  more  character- 
istic of  a  definite  law,  such  as  is  only  observed  in  connection  with  the 
formation  of  definite  chemical  compounds. 

Allen  and  Shepherd737  deny  that  this  constancy  of  composition  is 
due  to  the  reason  stated  and  regard  it  as  caused  by  the  constant  com- 
position of  the  mixture  charged  into  the  furnace.  They  endeavour  to 
support  their  contention  by  stating  that  many  minerals  have  been 
found  in  such  slags,  and  protest  against  speculations  on  the  structural 
chemical  nature  of  substances  of  which  the  molecular  weight  is  un- 
known. The  obvious  reply  to  such  a  criticism  is  that  it  is  quite  beside 
the  point.  There  is  no  evidence  in  support  of  the  view  that  the  com- 
position of  the  slags  is  dependent  on  that  of  the  charge,  except  in  so 
far  as  all  chemical  reactions  require  certain  proportions  of  raw  materials 
before  they  can  occur.  The  fact  that  the  charge  is  constant,  or 
variable  within  certain  limits,  is  not  incompatible  with  the  formation 
of  definite  chemical  compounds. 

The  further  allegation  that  such  slags  contain  many  minerals  is  not 
supported  by  facts.  Jantzen,  who  arrived  at  the  same  conclusion  as  the 
authors  of  the  H.P.  theory,  concerning  the  slags  he  examined,  must 
have  reached  a  widely  different  conclusion  if  the  slags  had  really  con- 
tained numerous  minerals. 

If  Allen  and  Shepherd  insist  on  regarding  slags  as  a  kind  of  "  glass," 
i.e.  as  a  mixture,  it  is  difficult  to  see  how  they  can  explain  satisfactorily 
the  results  of  Lunge's  experiments  (pp.  160  and  171)  on  the  behaviour  of 
granulated  and  ungranulated  slags  with  alkalies.  It  would  be  a  most 


THE   CONSTITUTION   OF   SLAGS 


171 


remarkable  coincidence  if  such  slags  behaved  so  completely  in  accord- 
ance with  the  H.P.  theory,  if  this  theory  were  quite  erroneous. 

With  regard  to  the  determination  of  the  molecular  weight  of  the 
constituents  of  slags,  it  is  one  of  the  advantages  of  the  H.P.  theory 
that  (as  has  been  previously  pointed  out)  it  furnishes  for  the  first  time 
a  fully  established  hypothesis  concerning  the  minimum  molecular 
weight  which  a  substance  can  possess  when  in  the  solid  form.  The 
determination  of  this  minimum  has  been  impossible  hitherto,  as  no 
method  yet  known — not  even  the  physico-chemical  ones  used  for 
soluble  compounds — is  applicable  to  solids.  The  published  molecular 
weights  are,  as  the  present  writers  have  shown  elsewhere,  only  applic- 
able to  substances  in  gaseous  form  or  in  solution,  and  cannot  be  used 
for  substances  in  a  solid  state.  The  charge  of  lack  of  knowledge  of 
molecular  weight  of  the  compounds  concerned  cannot,  for  this  reason, 
be  urged  in  opposition  to  the  H.P.  theory. 

Previous  theories  as  to  the  nature  of  furnace  slags  have  led  to  most 
puzzling  results.  The  theory  that  the  chief  constituent  of  these 
slags  is  a  definite  chemical  compound  is  confirmed  by  the  fact  that 
analytical  results  obtained  by  Jantzen  agree  well  with  the  formula  : 

26  CaO  •  1.5  MgO  •  0.25  FeO  •  0.25  MnO  •  3  A1203  •  18  Si02  •  CaS  •  0.5  CaS04 


° 


An  experimental  proof  of  the  authors'  views  of  the  constitution 
of  furnace  slags  is  to  be  found  in  an  investigation  of  slowly  cooled 
and  of  granulated  slags  by  Lunge305,  who  obtained  the  following 
results  : 

21.5  CaO  •  0.5  MgO  •  2  H20  •  6  A12O3  •  10  Si02  •  CaS 


,         \\     /  \/  \ ii  \ 

j  3°=<(si]  Al  |  Al|sT>=30  •  CaS  I 
V          II     \/\/     II  ' 


CaO 

Calculated   47.46 

Foundin \(a)    47.17 

Granulated  slag  )(b)    47.14 

Foundin l  (a)  46.38 

Ungranulated  slag/ (6)  46.40 


MgO 

0.78 

CaS 

2.82 

A1203 
23.93 

Si02 
23.60 

H20 
1.41 

t 

0.73 

1.82 

24.36 

23.38 

1.06 

0.72 

0.73 

1.82 

24.20 

23.60 

1.25 

0.84 

0.81 

1.79 

24.64 

23.29 

1.21 

0.98 

0.81 

1.79 

24.82 

23.50 

1.17 

1.10 

<f>  Unattacked  by  caustic  soda  or  sodium  carbonate. 


172 


CONSEQUENCES   OF   THE   H.P.   THEORY 


The  experiments  from  which  these  results  were  obtained  are  shown 
in  the  following  Table  : 


Nature  of  Treatment 

Dissolved  out  of  granu- 
lated slags 

Dissolved  out  of  ungranu- 
lated  slags 

iSiO, 

% 

Al,0, 

% 

Mol.  SiO, 
to  1  Mol. 
Al,0, 

SiO, 

% 

A1,0S 

% 

Mol.  SiO, 
to  1  Mol. 
Al,0, 

I.  Boiled  for  2  hrs.  with  30  per  cent  caustic  f 
soda  solution  \ 

6.93 
6.93 

1.09 

0.88 

2.30 
2.12 

1.92 
1.80 

3.53 
3.00 
3.52 

3.52 

1.26 
1.15 

1.19 
1.14 

5.94 

2.57 
2.33 

3.43 
3.53 

2.63 

2.74 

4.12 
4.81 
4.91 

4.40 

1.9 

0.72 
0.40 

1.15 
1.03 

1.25 
1.13 

1.47 
1.08 
1.23 

1.37 

7.25 
7.25 

1.76 
1.48 

2.68 

2.87 

2.49 
2.74 

4.25 
4.46 
4.46 

4.40 

4.68 
4.70 

5.06 
5.08 

6.39 
6.34 

0.15 
0.17 

0.13 
0.15 

0.12 
0.11 

0.31 

0.28 

1.91 
1.91 

II.  Boiled  for  2  hrs.  wfth  10  per  cent  caustic/ 
soda  solution  .      \ 

III.  Digested   for  6  hrs.  on  a  water  bath/ 
with  10  per  cent  caustic  soda  solution  \ 

IV.  Boiled  for  2  hrs.  with  5  per  cent  caustic/ 
soda  solution        \ 

V.  Digested  for  6  hrs.   on  a  water  bath] 
with  5  per  cent  caustic  soda  solution  1 

»         »>                 >j                 ft 
VI.  Boiled  for  2  hrs.  with  5  per  cent  sodium/ 

VII.  Heated  for  6  hrs.  on  a  water  bath  with  f 
5  per  cent  sodium  carbonate  solution  \ 

It  will  be  observed  that  a  30  per  cent,  solution  of  caustic  soda 
attacks  both  kinds  of  slag  so  strongly  as  to  resemble  the  effect  of 
fusing  them  with  soda.  For  this  reason  no  importance  should  be 
attached  to  the  fact  that  rather  more  is  dissolved  from  the  ungranulated 
slag  than  from  the  other.  The  relative  behaviour  of  both  slags  towards 
10  per  cent,  caustic  soda  solution  should  be  noted,  especially  the  fact 
that  the  granulated  slag  is  the  more  soluble  of  the  two.  On  comparing 
the  structural  formulae  of  the  two  slags 


3°=<(siJAl|Al|Si  V3°-CaS 


Granulated  Slag. 


Ungranulated  Slag. 


CaS. 


THE   HARDENING   OF   PORTLAND   CEMENTS          173 

this  difference  is  easily  understood.  Through  the  combination  of  a 
large  number  of  cement  molecules  to  form  a  combined  molecule 
the  strength  of  the  bonds  of  the  alumina  in  the  ungranulated  slags 
is  greatly  reduced. 

On  the  other  hand,  it  appears  as  if  the  combination  of  several 
silicate  molecules,  to  form  a  single  large  one,  weakens  the  bond  in  the 
pentites  ;  otherwise,  no  explanation  can  be  given  for  ungranulated 
slags  giving  up  4  to  5  times  as  much  silica  to  sodium  carbonate  solution 
as  do  granulated  slags. 

(c)  A  New  Theory  of  Hardening 

Various  theories  of  hardening  are  stated  briefly  in  the  Bibli- 
ography.3059- None  of  them  are  entirely  satisfactory,  hence  the  need 
for  a  fresh  hypothesis  based  on  the  hexite-pentite  theory. 

In  the  following  formulae  is  shown  the  composition  of  various 
hydrated  hexites,  derived  from  one  which  is  capable  of  taking  up 
hydroxyl  progressively,  i.e.  at  different  intervals  of  time  : 

I  I  I  ii 

_/\  _/\_        _X\_        _/\_ 

IxF       fxl 


6XOa      H2O'6X02      2H20'6X02 


I  I  I  II 

3H20'6XOj         4H2O*6XO2         5H2O'6XO2  6H2O-6X02 

d  e  f  g 

The  conversion  of  a  into  6,  b  into  c,  c  into  d,  and  so  on,  is  accom- 
panied by  an  increase  in  the  volume  of  the  molecules  concerned,  so 
that  the  molecular  volume  of  b  is  greater  than  that  of  a  ;  that  of  c  is 
greater  than  that  of  6,  and  the  compound  g  has  the  largest  molecular 
volume  of  the  whole  series. 

In  converting  the  compound  a  into  b,  b  into  c,  and  so  on,  the 
separate  molecules  in  each  group  take  up  definite  positions  relative 
to  each  other,  so  that  between  b,  c,  d,  e,  etc.,  definite  attractive,  or 
more  correctly  molecular,  forces  are  bound  to  exist. 

Assuming  the  molecules  to  be  in  the  form  of  minute  spheres,  the 
last  statement  may  be  expressed  graphically  by  the  following  diagrams  : 


b  Molecules  c  Molecules  d  Molecules 

Each  addition  to  the  molecule  of  water  in  the  form  of  hydroxyl 
groups,  305b  with  a  corresponding  increase  in  the  size  of  the  molecule,  is 
termed  a  hydration  phase.  It  is  clear  that  any  substance  which  is  sub- 
mitted to  a  sufficient  number  of  hydration  phases  must  set  and  harden, 
because  with  the  increase  in  the  molecular  volume  the  space  between 
the  various  molecules  must  diminish  and  their  mutual  attraction  or 
molecular  force  must  correspondingly  increase.  Hence,  every  substance 


174  CONSEQUENCES   OF   THE   H.R   THEORY 

which  can  take  up  water  progressively,  i.e.  which  can  undergo  a  series  of 
hydration  phases,  must  be  a  hydraulite  (see  footnote  p.  153). 

Experience  has  shown  that  if  the  first  hydration  phases  follow  each 
other  rapidly,  either  no  hardening  occurs  or  what  little  hardening 
takes  place  is  very  feeble. 

These  facts  may  be  explained  in  accordance  with  the  new  theory, 
by  stating  that  if  the  hydration  phases  follow  each  other  rapidly,  the 
spaces  between  the  molecules  are  too  large,  or  at  any  rate  much  larger 
than  when  the  hydration  occurs  more  slowly.  If  this  explanation  is 
correct,  it  should  be  possible  to  treat  substances  which  hydrate  rapidly 
and  do  not  harden  in  such  a  manner  (as  by  applying  pressure)  that  the 
molecules  are  brought  nearer  together.  The  facts  prove  that  when  this 
is  done,  the  substance  sets  and  hardens,  thus  fully  confirming  the 
theory.  Quicklime  is  a  typical  example  of  a  material  with  rapid 
hydration  phases,  and  when  it  is  slaked  it  falls  completely  to  powder 
with  a  considerable  development  of  heat  and  the  evolution  of  clouds  of 
steam.  According  to  Knapp306,  however,  very  finely  ground  quicklime 
when  mixed  with  water  in  a  suitable,  tightly  closed  vessel  produces, 
after  several  hours,  a  material  which  is  harder  than  ordinary  black- 
board chalk. 

From  the  foregoing  statements,  the  following  conditions  and 
characteristics  of  good  hydraulites  may  be  deduced  : 

1.  The  earlier  hydration  phases  must  occur  at  sufficiently  long 
intervals. 

2.  The  material  must  undergo  a  large  number  of  hydration  phases. 
Of  several  substances,  under  similar  conditions,  the  one  which  under- 
goes the  most  hydration  phases  will  eventually  be  the  hardest  and 
the  most  dense. 

3.  The  smaller  the  distance  between  the  molecules  of  a  hydraulite 
during  the  first  hydration  phases,  the  harder  and  denser  will  be  the 
mass  produced. 

The  New  Theory  of  Hardening  and  the  Facts 

I.  According  to  this  theory,  setting  must  be  prevented  if  the 
particles  of  hydraulite  are  too  far  apart,  as  when  too  much  water  is 
used.307     An  excess  of  water  may  also  bring   about   too   rapid   an 
addition  of  OH-groups  and  this,  according  to  the  new  theory,  must 
have  a  detrimental  effect. 

II.  It  also  follows  from  the  theory  that  the  smallness  of  the  hydrau- 
lite  particles   must   play  a   special   part  in   setting  and  hardening. 
The   smaller   the   particles   the   easier   and   more  rapid  will  be  the 
hydration  ;    the  larger  the  particles  the  more  difficult  will  it  be  to 
hydrate  them.    A  definite  degree  of  fineness  is,  therefore,  an  essential 
condition  of  hydration,  and  it  is  theoretically,  as  well  as  practically, 
necessary  to  regulate  the  intervals  of  time  between  the  hydration 
phases  (i.e.  the  rate  of  combination  with  water)  by  means  of  the  fine- 
ness of  the  particles  of  cement. 


THE   HARDENING   OF  PORTLAND   CEMENTS         175 

III.  According  to  Knapp308,  anhydrous  magnesia  (prepared  by 
calcining  magnesium  chloride)  absorbs  water  with  no  development  of 
heat  and  with  extreme  slowness,  a  stony  mass  is  produced  with  a  hard- 
ness somewhat  greater  than  that  of  marble.  The  lighter,  more  porous 
magnesia  (obtained  from  the  hydrous  carbonate)  combines  rapidly 
with  water  and  finally  forms  a  porous,  talc-like  mass. 

Richter309  maintained  finely  powdered,  anhydrous  calcium  nitrate 
at  a  white  heat  for  six  hours  in  a  platinum  crucible  and  obtained  a 
vitrified  porcelain-like  mass,  with  a  clearly  defined  crystalline  texture 
on  the  fractured  surface.  When  ground  with  water  this  crystalline 
CaO  sets  like  cement.  If  the  lime  is  insufficiently  heated  it  is  found  to 
crack  badly  on  cooling. 

Allen  and  Shepherd737  state  that  only  large  pieces  of  fused  lime  are 
indifferent  to  water,  and  that  finely  powdered,  fused  lime  does 
not  differ  from  ordinary  quicklime.  This  "  fact,"  which  requires  con- 
firmation as  it  contradicts  the  results  of  Richter's  investigations,  is  used 
by  Allen  and  Shepherd  as  evidence  against  the  H.P.  theory.  These 
critics  consider  that  the  reduced  reacting  power  of  the  burned  material 
is  not  due  to  polymerisation,  but  to  the  size  of  the  pieces,  i.e.  to  the 
surface  area.  If  this  were  really  the  case,  calcium  aluminosilicates 
(cements)  must  behave  exactly  the  same  when  burned  hard  or  soft, 
provided  that  the  material  is  ground  to  the  same  degree  of  fineness 
in  both  cases.  Direct  experiments  show,  however,  that  this  is  not  the 
case. 

These  interesting  instances  of  isomeric  lime  and  magnesia  are 
readily  understood  in  the  light  of  the  authors'  theory  ;  both  the  MgO 
from  magnesium  chloride  and  the  crystalline  CaO  are  polymerisation 
products  which  have  hydration  phases  like  the  hydraulites  and  harden 
in  a  similar  manner. 

According  to  the  authors'  theory,  the  cause  of  disintegration  in 
some  materials  is  due  to  hydration  phases  following  each  other  too 
rapidly,  owing  to  the  material  not  having  been  properly  burned.  In 
this  connection  it  must  be  admitted  that  disintegration  may  also  be 
due  to  other  causes. 

For  instance,  Michaelis310  attributes  the  cracking  or  "  expansion  " 
of  cements  to  a  subsequent  increase  in  volume,  this  being  due  to  three 
causes  :  first  and  foremost  to  a  high  percentage  of  lime,  second  to  the 
presence  of  calcium  sulphate,  and,  finally,  to  irregular  particles  and 
coarse  grains  in  the  cement. 

That  too  high  a  percentage  of  lime  may  bring  about  the  destruction 
of  the  mass  is  a  simple  inference  from  the  authors'  theory,  as  lime  and 
alkalies  effect  an  intense  and  rapid  hydration,  and  a  sufficiently  large 
proportion  of  lime  will  cause  the  hydration  phases  to  follow  each  other 
very  rapidly. 

An  irregular  distribution  of  coarse  and  fine  grains  in  the  cement, 
resulting  in  disintegration,  may  be  explained  in  terms  of  the  authors' 
theory  because,  as  already  mentioned,  a  fine  powder  is  hydrated  more 


176  CONSEQUEiNCES   OF  THE   H.P.   THEORY 

rapidly  than  a  coarser  one  and  forces  differing  in  intensity  are  thereby 
set  to  work  in  various  portions  of  the  material,  with  the  result  that  the 
latter  is  broken  up. 

The  harmful  effect  of  gypsum  or  plaster  of  Paris  in  silicate  cements 
is  described  later. 

IV.  Quartz  crushed  to  an  impalpable  powder  and  then  levigated, 
will  not  form  a  hard  mass  with  lime  and  water.311     Opal,  similarly 
treated,  hardens  slowly,  but  well.    Calcined  silica,  such  as  that  obtained 
in  silicate  analyses,  when  mixed  with  lime,  hardens  rapidly  but  badly. 

According  to  the  authors'  theory,  lime  effects  a  hydration  of  the 
opal  and  calcined  silica,  so  that  they  harden ;  but,  as  lime  does  not 
behave  in  this  way  towards  quartz,  with  the  last-named  substance  no 
hardening  occurs. 

According  to  Winkler312,  if  a  mixture  of  three  parts  of  quartz  and 
one  part  of  lime  is  strongly  heated  and  the  sintered  mass  is  then 
crushed  with  six  times  its  weight  of  lime  and  a  suitable  quantity  of 
water,  the  mass  hardens  slowly  and  strongly.  It  is  clear  that  in  this 
case  a  series  of  hydration  phases  occurs  at  long  intervals. 

V.  The   authors'   dynamisation   theory  also  explains   why  it   is 
necessary  for  most  silicates  to  be  heated  to  redness  before  they  will 
harden  in  water  (like  Portland  cements),  or  with  lime  and  water  (like 
puzzolans).    In  the  case  of  clays  it  has  already  been  shown  that,  on 
heating  them  to  redness,  or  on  causing  them  to  combine  with  a  base, 
the  bond  between  the  hexites  or  pentites  of  silicon  and  aluminium  is 
weakened,  and,  for  this  reason,  such  silicates  precipitate  gelatinous 
silica  when  treated  with  dilute  acids. 

The  authors'  theory  agrees  with  the  discovery  of  Fuchs  that  only 
those  silicates  harden  which  contain  "  soluble  silica,"  with  the  one 
difference  that  the  "  soluble  silica  "  plays  absolutely  no  part  in  the 
hardening  process. 

Different  silicates  must  be  heated314  to  very  different  temperatures 
or  for  various  periods  before  they  will  harden  with  lime  and  water. 
For  some  of  them  a  short  heating  to  redness  is  sufficient  ;  others  must 
be  strongly  heated  for  a  considerable  time,  and  others  must  be  almost 
melted.  According  to  Fuchs,  the  following  substances  harden  with 
lime  and  water  after  they  have  been  sufficiently  heated  at  a  suitable 
temperature  :  felspars,  leucite,  various  magnesium  silicates  such  as 
talc  and  steatite,  analcime,  natrolite,  clays,  etc.  All  these  silicates 
harden  because  the  heating  and  subsequent  treatment  with  lime  and 
water  produce  hydration  phases  in  the  manner  already  explained. 

The  cause  of  the  hardening  of  "  trass  "  and  "  puzzolans  "  with  lime 
and  water  may  be  explained  in  an  analogous  manner.  The  trasses  and 
puzzolans  are  simply  clays,  and  only  differ  from  ordinary  clays  in  the 
alterations  they  have  undergone  in  consequence  of  volcanic  action. 
In  the  course  of  time  these  substances  may  again  lose  their  free 
secondary  valencies.  Such  trasses  or  puzzolans  are  improved  by  being 
heated  to  redness. 


THE   HARDENING   OF  PORTLAND   CEMENTS 


177 


A  considerable  number  of  hydraulites  of  the  most  widely  different 
composition  have  already  been  prepared.  Thus,  various  aluminates, 
ferrites,  ferromanganese  oxides  and  silicates,  borates,  calcium  sul- 
phates, etc.,  have  marked  hydraulic  properties.  A  further  study  of  the 
hardening  of  these  compounds  must  eventually  lead  to  the  proof  of 
the  existence  of  hydration  phases. 

VI.  The  Causes  of  Hardening  of  Portland  Cements.  If  a  definite 
silicate  cement  is  selected,  e.g.  the  compound 


4°= 


Si   Al  Al   Si 


the  following  substances  may  be  formed  from  it  : 


-f  2  Ca(OH), 


(2) 


+4  Ca(OH)2 


etc.  etc. 


If  the  hydration  occurs  as  indicated  in  the  above  formulae  at  definite 
intervals  and  with  a  definite  increase  in  volume,  hydraulites  are  pro- 
duced in  accordance  with  the  authors'  theory.  The  absorption  of 
water  does  actually  occur  in  this  manner,  as  will  be  explained  in  the 
next  chapter  ;  Zulkowski315  has  experimentally  proved  the  increase  in 
volume.  He  treated  ground  slag  with  water,  and  obtained  a  flocculent 


178  CONSEQUENCES   OF   THE   H.P.  THEORY 

mass  and  a  deposit  of  a  sandy  nature.  The  volume  of  the  deposit 
increased  in  process  of  time.  The  microscopical  appearance  of  this 
ground  slag  after  treatment  with  water  differed  but  little  from  that  of 
the  dry  (untreated)  material. 

The  action  of  alkaline  fluids  was  much  more  energetic.  The  volume 
of  the  deposit  was  three  to  five  times  that  of  the  original  slag-powder. 
Under  the  microscope  the  appearanceof  the  material  gradually  changes, 
and  after  several  months  the  original,  small,  glassy  grains  were  no 
longer  observable,  their  place  being  taken  by  much  larger,  irregular 
rounded  grains  or  masses. 

In  the  case  of  Portland  cement,  water  alone  will  effect  a  change  in 
shape  similar  to  that  which  occurs  with  slag-meal  and  alkaline  solu- 
tions. Zulkowski  was  the  first  to  point  out  these  changes  in  shape 
and  volume  in  the  case  of  silicate  cements,  and  in  these  changes  he 
saw  the  true  cause  of  the  hardening  of  hydraulic  materials.  The 
hardening  itself  he  explains  as  follows  :  "  The  cement  grains  which,  at 
the  commencement,  lie  over  and  amongst  each  other  and  without  any 
definite  relationship  to  each  other,  combine  chemically  with  the  water 
present  in  the  pores  ;  from  them  is  produced  a  new  substance,  a 
hydrosilicate,  the  material  thereby  changing  its  shape  and  increasing  in 
volume.  The  particles  which  expand  in  this  manner  occupy  all  the 
available  space,  lie  closely  together,  increase  continually  in  volume, 
and  eventually  convert  the  whole  of  the  original  loose  particles  into  a 
compact  mass." 

[W.  Michaelis  (Chem.  Zeit.,  1893,  17,  982)  has  suggested  that  hardening  is  mainly 
due  to  the  formation  of  a  colloidal  calcium  hydrosilicate.  According  to  Desch709, 
"  this  theory  so  well  explains  the  phenomena  observed  and  is  in  such  good  accordance 
with  the  results  of  microscopical  investigation  of  cements  during  and  after  setting 
that  it  must  be  held  to  contain  the  greater  part  of  the  truth."  Desch  further  adds 
that  "  the  course  of  events  when  Portland  cement  is  mixed  with  water  may  be  described 
as  follows  :  The  essential  hydraulic  constituent  is  alite,  which  is  a  solid  solution  of 
three  components.  The  action  of  the  water  is,  at  first,  confined  to  the  alite,  which 
is  partly  decomposed,  the  aluminates  being  first  hydrolysed.  The  solution  thus  pro- 
duced is  supersaturated  and  soon  deposits  tricalcium  aluminate  partly  in  colloidal 
form  and  partly  in  crystals,  according  to  the  amount  of  water  in  the  mixture,  a  larger 
proportion  of  water  favouring  crystals  and  a  smaller  one  the  formation  of  a  gel.  The 
excess  of  lime  remains  in  solution  or  a  part  may  be  deposited  as  crystals  of  calcium 
hydroxide.  This  corresponds  to  the  '  initial  set.' 

"  The  action  of  the  water  on  the  calcium  silicate  contained  in  the  alite  is  much 
slower,  and  when  hydrolysis  occurs  the  calcium  silicate  is  separated  in  colloidal  form. 
The  gel  produced  forms  a  coating  round  the  particles  and  prevents  further  action. 
The  colloidal  matter  is  easily  seen  in  a  polished  and  etched  specimen,  and  its  definitely 
colloidal  nature  may  be  shown  by  immersion  in  a  dye  such  as  eosin.  Colloidal  sub- 
stances adsorb  dyes,  but  crystals  do  not  do  so." 

Desch  attributes  the  hardening  of  cement  which  has  been  hardened  and  re-ground 
to  the  large  proportion  of  non-hydrated  matter  present  in  all  cements,  owing  to  the 
slowness  of  the  hydration. 

The  suggestion  of  W.  Michaelis  that  the  hardening  of  cements  is  due  to  their 
colloidal  nature  cannot  per  se  be  regarded  as  of  more  than  limited  value,  even  when 
supported  by  the  statement  of  C.  Desch  that  it  "  is  in  such  good  accordance  with  the 
results  of  microscopical  investigation."  It  does  not  coincide  with  the  results  of 
Feichtinger's  studies  of  hydration,  given  on  another  page,  nor  with  the  thermal  in- 
vestigations of  Oswald  and  the  multitude  of  facts  which  have  been  published  in 
support  of  various  other  theories,  and  is  therefore  inapplicable  to  any  general  theory 
relative  to  cements.  There  is  an  analogy  between  the  action  of  water  on  cements 
and  on  colloids,  as  has  been  pointed  out  on  a  previous  page,  and  any  theory  (if 


FORMULA   OF  PORTLAND  CEMENTS 


179 


correct)  must  therefore  be  capable  of  extension  to  organic  cements  in  which  hydrosols 
are  converted  into  hydrogels,  forming  cementitious  substances,  just  as  inorganic 
cements  pass  through  definite  hydration  phases  into  stone-like  masses. 

Bone-substance,  which  is  essentially  a  highly  basic  calcium  carbo-phosphate 
(p.  271),  is  probably  derived  from  an  organic  cement  whose  hardening  phases  are 
analogous  to  those  of  Portland  cement.] 


The  Consequences  of  the  New  Theory  of  Portland  Cement 
and  the  Facts 

From  the  foregoing  theory  of  the  chemical  constitution  of  the 
Portland  cements  and  the  corresponding  hardening  theory,  a  series  of 
interesting  consequences  may  be  inferred,  the  value  of  which  may  be 
proved  by  means  of  the  experimental  material  available. 


From  the  theory  it  follows  that  the  calculation  of  the  formulae 
of  Portland  cements  from  their  analyses  must  lead  to  compounds,  the 
existence  of  which  is  theoretically  possible.  The  calculation  of  the 
formulae  from  a  series  of  cement  analyses  fully  confirms  this  conse- 
quence of  the  theory  ;  the  high  content  of  bases  is  particularly  notice- 
able in  some  analyses.  Whether  the  whole  of  the  base  is  in  actual 
combination  is  doubtful ;  further  investigations  are  needed  to  decide 
it. 

The  formulae  calculated  from  cement  analyses  (see  Appendix)  are 
shown  in  the  following  Tables  : 

(a)  n  MO  •  3  R2O3  -  12  Si02  -  2. 


Al,0, 

Fe,0, 

CaO 

MgO 

K,0 

Na,O 

SO, 

CO, 

H,0 

I.  24  MO     3  R203     12  SiO2  •  2 

1.50 

.50 

26.00 

1.00 

0.25 

0.25 

0.5 

3 

2 

II.  34  MO     3  R203     12  SiO2 

2.00 

.00 

34.00 

— 

— 

— 

— 

— 

— 

III.  35  MO     3  R203     12  SiO2 

2.00 

.00 

35.00 

— 

— 

— 

— 

— 

— 

kIV.  36  MO     3  R203     12  SiO2     2 

2.00 

.00 

36.00 

0.50 

— 

0.5 

— 

— 

V.  37  MO     3  R2O3     12  SiO2     2 

2.00 

.00 

36.00 

1.50 

— 

0.5 

— 

— 

VI.  37  MO     3  R2O3     12  SiO2    S 

2.00 

.00 

36.25 

1.25 

— 

— 

0.5 

— 

— 

VII.  37  MO     3  R2O3     12  SiO2    S 

2.25 

0.75 

36.00 

2.00 

— 

— 

1.0 

— 

— 

VIII.  38  MO     3  R2O3     12  SiO2    S 

2.25 

0.75 

38.00 

0.50 

— 

— 

0.5 

— 

— 

IX.  39  MO     3  R2O3     12  SiO2    S 

2.00 

1.00 

38.25 

1.25 

— 

— 

0.5 

— 

— 

X.  39  MO     3  R2O3     12  SiO2    2 

2.50 

0.50 

39.00 

1.00 

— 

— 

1.0 

— 

— 

(b)  n  MO  •  3  R203  •  10  Si02. 


Al,0, 

Fe,0, 

CaO 

MgO 

K,0 

Na,0 

SO, 

CO, 

H,0 

XI.  29  MO  •  3  R208  -  10  SiO2 
XII.  34  MO  •  3  R2O3  •  10  SiO2 
XIII.  35  MO  •  3  R2O3  •  10  SiO2 

3.00 
2.25 
2.25 

0.75 
0.75 

29.0 
31.5 
32.5 

2.5 
1.5 

0.5 

0.5 

_  __ 

— 

2 

(c)  n  MO  •  3  R2O3  •  18  Si02 

.  v 
£j. 

|lAl,0, 

Fe,0, 

CaO 

MgO    K,O 

Na,0 

SO, 

CO, 

H,0 

XIV.  52  MO  •  3  R2O3  •  18  SiO2 
XV.  54  MO  •  3  R2O3  •  18  SiO2  •  S 

2.25 

3.00 
0.75 

52.00 
53.75 

1.25   — 

___ 

1 

__ 

___ 

180  CONSEQUENCES   OF  THE   H.P.   THEORY 

(d)  n  MO  •  3  R203  •  15  SiO2  •  2. 


AlaO, 

Fe,0, 

CaO 

MgO 

Kto 

Na,O 

SO, 

co,    |H,O 

XVI.  20  MO  •  3  B2O3     15  SiO2  •  S 

2.00 

1.00 

22.0 

1.0 

0.25 

0.25 

0.50)  3.0 

1 

XVII.  21  MO  •  3  R2O3     15  SiO2  •  S 

2.00 

1.00 

22.0 

0.5 

— 

— 

0.50 

1.0 

2 

XVIII.  21  MO  •  3  R203     15  SiO2  •  S 

2.00 

1.00 

22.5 

1.0 

0.25 

0.25 

0.50 

2.5 

1 

XIX.  22  MO  •  3  R2O3     15  SiO2  •  S 

2.00 

1.00 

22.0 

0.5 

0.25 

0.25 

0.50 

0.5 

2 

XX.  24  MO  •  3  R2O3     15  SiO2  -  S 

1.50 

1.50 

26.5 

.5 

— 

0.25 

0.25 

4.0 

2 

XXI.  25  MO  •  3  R2O3     15  SiO2  •  S 

1.50 

1.50 

27.0 

1.5 

0.25 

0.25 

— 

4.0 

2 

XXII.  39  MO  •  3  R2O3     15  SiO2  •  S 

2.50 

0.50 

36.0 

2.5 

0.50 

0.50 

1.00 

O.SMnO 

XXIII.  42  MO  •  3  R2OS     15  SiO3  •  S 

2.00 

1.00 

42.5 

.5 

0.50 

0.50 

0.50 

2.5 

2 

XXIV.  45  MO  •  3  R2O3     15  SiO2  •  S 

2.50 

0.50 

45.0 

.0 

— 

— 

1.00 

— 

— 

XXV.  45  MO  •  3  R2O3     15  SiO2  •  S 

2.25 

0.75 

44.0 

1.0 

0.25 

0.75 

1.00 

— 

— 

XXVI.  46  MO  •  3  R2O3     15  SiO2  •  S 

2.25 

0.75 

45.5 

.0 

— 

— 

0.50 

— 

— 

XXVII.  46  MO  •  3  R2O3     15  SiO2  •  S 

2.25 

0.75 

46.0 

.0 

— 

— 

1.00 

— 

— 

(e)  n  MO  -  6  R203  •  12  SiO2  •  2. 


A1,O, 

Fe,0, 

\C&0 

MgO 

K,0 

Na,o| 

SO, 

CO,   H,0 

XXVIII. 

92  MO- 

6  R203  • 

12  SiO2  •  2  |     5 

1 

I  89 

6 

-1-   1 

— 

3    |10 

(f)  n  MO  -  6  R2O3  •  18  Si02  •  2. 


Fe,0,  |  CaO  |  MgO  |  K,O  |Na,O  |  SO,     CO, 


XXIX.  38  MO  -  6  R2O3  •  18  SiO2  •  S 

3.5 

2.5 

40.0 

_ 



0.5 

0.5 

2 

2 

XXX.  39  MO  •  6  R2O3  •  18  SiO2  •  S 

3.5 

2.5 

40.5 

0.5 

— 

0.5 

0.5 

2 

2 

XXXI.  74  MO  •  6  R2O3  -  18  SiO2  •  S 

5.0 

1.0 

71.0 

6.0 

— 

— 

— 

3 

8 

XXXII.  76  MO  •  6  R2O3  •  18  SiO2  •  S 

5.0 

1.0 

72.0 

5.0 

— 

— 

— 

1 

4 

XXXIII.  90  MO  •  6  R2O3  •  18  SiO2  •  S 

5.0 

1.0 

86.0 

8.0 

— 

— 

— 

4 

10 

(g)  n  MO  •  6  R203  •  16  Si0 


Fe,0,    CaO     MgO    K,O   Na,O  SO,  CO, 


XXXIV.  36MO-6R203-16Si02-2 

6 



35.50 

3.50 





1,0 

2.00 

30 





XXXV.  38MO-6R203-16Si02-2 

6 

— 

35.75 

3.25 

0.50 

0.50 

1.5 

1.50 

36 

0.5 

0.5 

XXXVI.  39MO-6R203-16Si02-2 

6 

— 

34.00 

3.00 

1.00 

1.00 

1.0 

— 

— 

0.5 

0.5 

XXXVII.  39MO-6R203-16Si02-2 

6 

— 

35.75 

3.25J  0.50 

1.00 

1.5 

1.00 

30 

0.5 

0.5 

XXXVIII.  40MO-6R203-16Si02-S 

6 

— 

34.75 

3.25  0.75 

1.00 

0.5 

0.25 

— 

0.5 

0.5 

(h)  n  MO  •  5  R2O3  •  18  SiO2  .  2. 


Al,0,  |  Fe,0,  |  CaO  JMgO  |  K,O  [N%0  j  SO,  |  CO,  |H,O 


XXXIX.  44  MO  •  5  R203  •  18  SiO,  •  S 
XL.  50  MO  •  5  R2O3  •  18  SiO2  •  S 

3.5 
4.0 

1.5 
1.0 

44.5 
50.0 

1.0 
1.0 

0.5 

1.5 

0.5 
1.0 

o 

2.5 

(i)  n  MO  •  R203  •  12  Si02. 


Al,0,     Fe,0s     CaO      MgO      K,O     Na,O    SO,     CO,    H,O 


XLI.  30  MO  -  R203  •  12  SiO2 

0.75 

0.25 

29.5 

0.5 











XLII.  32  MO  •  R203  -  12  SiO2 

0.75 

0.25 

32.0 

— 

— 

— 

— 

— 

— 

XLIII.  34  MO  •  R2O3  •  12  SiO2 

1.00 

— 

33.5 

0.5 

— 

— 

— 

— 

— 

XLIV.  39  MO  •  R2O3  -  12  SiO2 

1.00 

— 

39.0 

— 

— 

— 

— 

— 

— 

The  water  which  enters  into  combination  must,  in  any  case,  be 
capable  of  representation  by  stoichiometrical  figures,  i.e.  in  molecules. 
That  this  can  be  done  is  seen  from  the  following  examples  : 


HYDRATION   OF  PORTLAND  CEMENTS 


181 


I.  Von  Teicheck316  has  studied  the  hydration  of  a  Portland  cement 
of  the  formula 


45  MO  •  3  R203 


15  SKX 


/  45  MO  =  44  CaO  •  1  MgO, 

\  3  Rao3  =  2.25  A1203  •  0.75  Fe203, 

R;0=  0,75  Na20  •  0.25  K20 
(see  Appendix,  Analysis  XXV). 


Al 


5V— ^  5° 

After  21  or  30  days  14-44  per  cent,  of  hydration-water  was  found, 
which,  according  to  theory,  represents  the  addition  of  36  mols.  of  water, 
as  shown  in  the  following  equation  : 

45  MO  •  3  R203  •  15  Si02  •  R'2SO4  +  36  H2O 
=  18  MO  •  9  H20  •  3  R2O3  •  15  SiO2  +  27  M(OH)2  -f  R2S04 

In  this  case,  the  chief  products  of  the  reaction  may  be  represented 
by: 

(1) 
(1) 


4-  27  M(OH)2 


The  percentage  of  water  represented  by  the  above  formula  is  14*21, 
which  is  in  sufficiently  close  agreement  with  that  found  by  experiment. 

II.  Zulkowski317  produced  a  cement  by  burning,  at  a  white  heat  in 
a  Seger  furnace,  a  mixture  of  lime  and  Zettlitzer  kaolin,  the  latter 
having  a  composition  corresponding  to  A12O3  •  2Si02  •  2H2O.  His 
results  suggest  one  of  the  two  following  formulae  for  the  cement  he 
prepared  : 


4°= 

4°= 


5°  5° 

II  II 

'\/V\/\=4o 

Si|Al|Al  Si' 

\/\/\/\/ 

II  II 

5°  5° 

36  CaO  -  6  A12O3  •  12  SiO 


!=4C 


or 


I  AI|  si  |_; 
\/y- 

4° 
36  CaO  •  6  A1203  •  12  SiO 


182 


CONSEQUENCES   OF  THE   H.P.  THEORY 


Zulkowski  studied  the  hydration  of  this  compound  by  reducing  it 
to  a  powder,  mixing  it  with  water  and  forming  balls ;  these  set  when 
warmed  gently  for  a  quarter  of  an  hour  and  became  quite  hard  after 
one  and  half  hours.  These  balls  were  then  placed  in  water  and  were 
found  to  have  become  much  harder  after  the  lapse  of  several  months. 

Zulkowski  also  found  that  a  given  cement  after  7  days  contained 
16-19%  and  after  30  days  17-05%  of  hydration- water.  According  to 
theory,  36  mols.  of  water  should  enter  into  combination  according  to  the 
following  equation  : 

36  CaO  •  6  A1203  •  12  Si02  +  36  H20 

H0(l) 
OH     /\/\/\/\     OH 


(1) 


28  Ca(OH)2* 


(1)OH          H0(l) 

The  value  16-19%  calculated  from  this  formula  agrees  sufficiently 
well  with  the  amount  found  by  experiment. 

C 

The  hydration  of  cements  must  take  place  very  gradually.  In 
determining  the  amount  of  water  entering  into  combination  during  the 
hardening  it  is,  therefore,  necessary  to  be  able  to  trace  a  gradual 
increase  in  the  proportion  of  water  in  the  material.  This  is  confirmed 
by  the  results  of  a  series  of  hydration  experiments  by  Feichtinger319, 
who  studied  the  behaviour,  towards  water,  of  the  following  hydraulic 
materials  : 


3°=<    Si 


3°= 


^ 

2°        3° 

21  MO  •  3  R203  - 15  Si02  •  2f  22  CaO  •  3  R2O3  •  15  Si02  •  2J 

(Analysis  XVIII,  Appendix)  (Analysis  XIX,  Appendix) 

1  (B)  2  (c) 

*  4000.8  gms.  of  the  hardened  cement  mass  contain  18x36  =  648  gms.  water  or 

4000  8=16>19 per cent*  water- 

t  2=2.5  R'COs  +  0.5  R2SO4+H2O. 
j  2=0.5  MgCOs  +  0.5  R2SO4  +  2  H2O. 


HYDRATION   OF   PORTLAND   CEMENTS  183 

4°  4°  3°  3° 


Si   Al    Si   Al    Si      go  -2 


4°  4°  4° 

44  CaO  •  5  R203  •  18  Si02  •  2*  26  CaO  •  6  R203  •  18  SiO2  -2f 

(Analysis  XXXIX,  Appendix)  (Analysis  XXX,  Appendix) 

3  (A)  4  (D) 

Samples  B,  C  and  D  were  Bavarian  hydraulic  limes,  obtained  by 
burning  marl ;  A  was  a  Portland  cement.  The  sample  D  con- 
tained 13  mols.  free  lime  (as  shown  by  Feichtinger's  experiments), 
but  in  the  other  silicates  the  whole  of  the  lime  was  in  a  combined 
state. 

The  hydration  experiments  were  carried  out  as  follows  :  a  small 
quantity  of  cement  was  placed  in  a  suitable  vessel  and  weighed  accu- 
rately. It  was  then  mixed  with  a  little  water  and  was  afterwards 
immersed  in  water.  To  determine  the  amount  of  water  which  had 
entered  into  combination,  the  samples  were  dried  at  100°  C.  and  the 
increase  in  weight  was  attributed  to  the  combined  water. 

Calcium  hydrate  only  loses  all  its  water  at  a  red  heat  ;  at  300°  C. 
only  a  portion  of  it  is  removed.  According  to  Feichtinger,  the  silicate- 
water  is  also  driven  off  at  this  temperature.  By  determining  the 
proportion  of  water  evolved  at  300°  C.  and  deducting  it  from  the 
total  combined  water,  the  difference  shows  the  proportion  of  water  in 
combination  with  the  lime. 

The  following  Tables — which  are  based  on  Feichtinger's  researches 
— show  the  manner  in  which  the  water  was  evolved. 

In  Table  I  : 

<7=the  total  weight  of  water  which  combines  with  100  parts  of 
cement  in  time  t. 

s=the  weight  of  water  which  is  evolved  at  a  red  heat  from 
100  parts  of  the  mixture  of  cement  and  water  at  300°  C,  i.e. 
water  combined  with  the  silicate. 

g — s= the  weight  of  water  which  is  evolved  at  red  heat  from 
100  parts  of  the  mixture  of  cement  and  water,  i.e.  water  com- 
bined with  lime  as  Ca(OH)2. 

*  2=1.5  R"CO3+1.5  R2CO3+0.5  R2SO4+2.5  H8O. 
t  2=2  R*CO3+0.5  Na2SO4+13  CaO +  2  H2O. 


184 


CONSEQUENCES   OF  THE   H.P.   THEORY 


Table  I 


1(B) 

2(C) 

MA) 

( 

4)D 

t 

g 

s 

g—s 

9 

8 

9—  s 

9 

8 

9—  8 

9 

8 

9—  * 

Immediately 

after  mixing 

with  water. 

1.28 

1.28 



0.61 

0.61 



0.99 

0.99 

— 

6.79 

1.40 

5.39 

After  4  hrs. 

1.67 

1.67 



0.71 

0.71 



1.41 

1.41 

— 

7.80 

2.42 

5.38 

,     20  „ 

2.08 

2.08 



1.14 

1.14 



2.29 

1.60 

0.69 

8.26 

3.08 

5.18 

,       3  days 

3.42 

3.42 



1.82 

1.82 



5.62 

3.80 

1.82 

8.87 

3.30 

5.57 

,       7     „ 

3.85 

3.85 



2.15 

2.15 



6.58 

4.76 

1.82 

11.20 

4.20 

7.00 

,     14     „ 

4.46 

4.46 



2.63 

2.63 



7.96 

5.90 

2.06 

11.80 

4.64 

7.16 

,     18     „ 

5.00 

4.40 

0.60 

2.84 

2.84 



8.45 

6.20 

2.25 

11.86 

4.60 

7.26 

,     21     „ 

5.84 

4.50 

1.34 

3.46 

3.46 



8.91 

6.43 

2.48 

12.75 

5.30 

7.45 

,     24     „ 

5.89 

4.42 

1.47 

4.36 

4.36 



10.40 

6.60 

3.80 

13.68 

5.60 

8.08 

,     28     „ 

6.86 

4.46 

2.40 

4.90 

4.30 

0.60 

10.52 

6.50 

4.02 

13.92 

5.82 

8.10 

,     35     „ 

7.68 

4.52 

3.16 

5.56 

4.25 

1.31 

11.43 

6.63 

4.80 

14.30 

6.18 

8.12 

,     42     „ 

8.30 

4.48 

3.82 

6.20 

4.30 

1.90 

11.35 

6.60 

4.75 

14.68 

6.60 

8.08 

,     49     „ 

8.92 

4.40 

4.52 

7.08 

4.20 

2.88 

11.50 

6.58 

4.92 

14.50 

6.56 

7.94 

,     56     „ 

9.13 

4.46 

4.67 

7.34 

4.25 

3.09 

11.60 

6.64 

4.96 

14.73 

6.60 

8.13 

,     80     „ 

9.50 

4.40 

5.10 

7.40 

4.20 

3.20 

11.56 

6.60 

4.96 

14.65 

6.56 

8.09 

In  Table  II  : 

MJ  ^i>  M2   and  MS  are  the  molecular  weights  of  the  hydraulic 

binding  materials. 
y=the  number  of  molecules  of  water  which  combine  with  /UL,  /z1? 

etc.,  parts  of  cement  in  time  t. 
<r=the  amount  of  water,  in  gramme-molecules,  lost  by  /x>  Mi>  e^c-> 

parts  of  the  mixture  of  cement  and  water  at  300°,  i.e.  water 

combined  with  the  silicate. 
y — cr=the  number  of  molecules  of  water  which  are  only  evolved  at 

a  red  heat  from/*, Mi>  etc->  parts  of  the  mixture  of  cement  and 

water,  i.e.  water  combined  with  lime  as  Ca(OH)2. 

Table  II 


M=2777.4 

/ii=2659.4 

/*2=4585 

^3=4327 

1  (B) 

2  (C) 

3  (A) 

4(D) 

t 

7 

<r 

7  -  G 

7 

<r    \y-ff 

7 

ff 

y-ff 

7       I      <f 

y-<T 

Immediately 

1 

after  mixing 

with  water. 

1.97 

1.97 

— 

0.90 

0.90 

— 

2.50 

2.50 

16.30 

3.36 

12.94 

After  4  hrs. 

2.58 

2.58 



1.04 

1.04 



3.59 

3.59 

18.75 

5.82J  12.93 

„     20  „ 

3.21 

3.21 



1.68 

1.68 



5.97 

4.07 

1.90 

19.86 

7.40  12.46 

„       3  days 

5.27 

5.27 

— 

2.69 

2.69 

— 

14.32 

9.68 

4.64 

21.33 

7.931  13.40 

„       7     „ 

5.94 

5.94 



3.17 

3.17 



16.77 

12.13 

4.64 

26.93 

10.19 

16.74 

„     14     „ 

6.88 

6.88 



3.97 

3.97 

— 

20.28 

15.04 

5.24 

28.37 

11.16117.21 

„     18     „ 

7.73 

6.79 

0.94 

4.19 

4.19 

— 

21.53 

15.80 

5.73 

28.51 

11.06 

17.45 

,,     21     „ 

9.01 

6.94 

2.07 

5.11 

5.11 

— 

22.70 

16.38 

6.32 

30.65 

12.74 

17.91 

„     24     „ 

9.08 

6.82 

2.26 

6.44 

6.44 

— 

26.50 

16.82 

9.68 

32.89 

13.46  19.43 

»     28     „ 

10.58 

6.88 

3.70 

7.24 

6.35 

0.89 

26.80 

16.95 

9.85 

33.46 

13.99 

19.47 

„     35     „ 

11.85 

6.97 

4.88 

8.21 

6.28 

1.93 

29.13 

16.89 

12.24 

34.38 

14.85 

19.53 

»     42     „ 

12.81 

6.91 

5.90 

9.16 

6.35 

2.81 

28.92 

16.82 

12.10 

35.29 

15.87 

19.42 

„     49     „ 

13.76 

6.79 

6.97 

10.46 

6.20 

4.26 

29.30 

16.77 

12.53 

34.83 

15.77 

19.08 

„     56     „ 

14.09 

6.88 

7.21 

10.85 

6.28 

4.57 

29.56 

16.92 

12.64 

35.41 

15.87 

19.54 

„     80     „ 

14.66 

6.79 

7.87 

10.93 

6.20 

4.73 

29.45 

16.82 

12.63 

35.22 

15.77  19.45 

HYDRATION   OF  PORTLAND   CEMENTS  185 

These  Tables  agree  with  the  theory  in  showing  a  gradual  absorption 
of  water.  Thus  1  B,  Table  II,  shows  that  on  mixing  the  cement  and 
water  together  only  2  mols.  H20  enter  into  combination,  but  that  after 
20  hours  3  mols.,  and  after  18  days  7  mols.  of  water  are  combined.  A 
gradual  combination  of  water  may  also  be  observed  in  the  case  of 
silicates  2(0),  3(A)  and  4(D). 

It  should  be  noticed  that,  according  to  Table  II,  some  of  the  CaO 
in  the  materials  studied  by  Feichtinger  split  off  before  the  silicates 
had  taken  up  the  maximum  quantity  of  water.  Thus  1(B)  can  bind  a 
maximum  of  9  mols.  of  water,  but  the  lime  splits  off  when  only  7  mols. 
(after  18  days)  are  combined.  After  80  days  this  silicate  took  up  no 
further  quantity  of  water.  A  similar  result  is  observable  with  2(0), 
which  is  analogously  constituted.  In  this  case,  the  lime  separates 
when  6  mols.  have  entered  into  combination,  but  only  after  28  days. 
With  Portland  cement  3(A)  the  lime  separates  after  the  combination 
of  4  mols.  of  water,  i.e.  after  20  hours.  In  the  compound  4(D)  the 
hydration  of  the  silicate  molecule  occurs  somewhat  rapidly,  on  account 
of  the  presence  of  free  lime.  After  20  hours  the  silicate  molecule 
combined  with  about  7-5  mols.  H20.  The  separation  of  the  lime  began 
only  after  3  days,  after  8  mols.  of  water  had  entered  into  combination. 

The  structural  formulae  1(B),  2(0),  3(A)  and  4(D)  show  clearly  the 
reason  for  the  separation  of  the  lime  at  an  earlier  stage  than  is  the 
case  with  other  hydraulites.  The  larger  the  basic  side-chains  the 
weaker  must  be  the  bond  of  a  portion  of  the  lime.  The  structural 
formula  of  Portland  cement  shows  4°-  and  5°-  side-chains,  whereas  the 
structural  formulae  of  the  other  compounds  show  at  most  only  2°-  or 
3°-  side-chains. 

The  figures  16. 82  and  15.77  molecules  of  o-water,*  which  are  taken 
up,  after  80  days,  from  the  compounds  3(A)  and  4(D),  at  first  appear  to 
be  opposed  to  the  authors'  theory,  as  for  the  latter  the  maximum  is  10 
mols.  a- water  (or  11  or  12  mols.  if  the  Al-OH-groups  are  included). 
From  Feichtinger 's  results  it  is,  however,  clear  that  part  of  the  water 
he  regarded  as  o-water  was  really  in  the  form  of  "  water  of  crystallisa- 
tion." Feichtinger  re-heated  the  cement  masses  1(B),  2(C),  3(A)  and 
4(D)  to  redness  and  obtained  a  fresh  hydration.  These  results  are 
shown  in  Tables  III  and  IV.  From  Table  IV  it  will  be  seen  that  the 
cements  3(A)  and  4(D)  give  similar  results  for  a-.  But,  shortly  after  mix- 
ing, the  cement  3(A)  took  up  7.49,  and  cement  4(D)  3.6  mols.  of  water,  so 
that  this  portion  of  the  water  behaves  differently  from  the  remainder. 
If  these  amounts  are  regarded  as  "  water  of  crystallisation,"  the 
remainder  (16.82- 7.49=9.33,  and  15.77-3.6=12.17)  may  be  termed 
*4  water  of  constitution,"  i.e.  the  compound  3(A)  has  taken  9,  and  4(D) 
about  12  mols.  of  silicate-water  into  combination  in  the  form  of 
hydroxyl  groups. 


For  definition  of  <r- water  sea  previous  page. 


186 


CONSEQUENCES   OF  THE   H.P.   THEORY 


In  silicate  cements,  such  as  Portland  cement,  which  are  devoid  of 
free  lime  there  can  only  be  one,  or  at  most  two  forms  of  water  present  at 
the  beginning  of  hydration,  viz.  silicate-water  and  "  water  of  crystallis- 
ation." After  a  short  time  a  third  form  of  water — that  in  the  calcium 
hydroxide  Ca(OH)2 — may  be  present.  If,  on  the  contrary,  the  cements 
contain  free  lime,  the  calcium  hydroxide  water  is  present  at  first  in 
addition  to  the  silicate-water  and  the  "  water  of  crystallisation  "  just 
mentioned. 

These  theoretical  deductions  are  confirmed  by  Feichtinger's  results 
previously  mentioned.  A  glance  at  Tables  I  and  II  will  show  that 
Feichtinger  found  no  calcium  hydroxide  water  in  cements  1(B),  2(C) 
and  3(A)  (which  contain  chemically  combined  lime),  but  in  cement 
4(D),  on  the  contrary,  he  found  it  shortly  after  the  commencement  of 
the  hydration.319* 

E 

From  the  hardened  masses  it  must  be  possible,  by  burning  under 
certain  conditions,  to  reproduce  the  original  hydraulite  with  exactly 
the  same  hydrating  (hardening)  properties,  so  long  as  water  is  the  sole 
hardening  agent,  as  was  the  case  in  Feichtinger's  experiments. 

Several  investigators,  and  particularly  Michaelis320,  have  drawn 
special  attention  to  the  possibility  of  reproducing  the  original  cement 
powder  from  the  hardened  mass.  This  possibility  of  regenerating 
cements  is,  however,  a  simple  deduction  from  the  results321  obtained 
by  Feichtinger,  who  endeavoured  to  ascertain  experimentally  whether 
a  hardened  cement  mortar  when  heated  to  redness  and  again  mixed 
with  water  will  re-set  and  harden.  He  also  measured  the  amount  of 
water  taken  up.  His  results  are  shown  in  the  following  Tables,  in 
which  the  letters  are  the  same  as  those  in  Tables  I  and  II. 


TABLE  III 


1(B) 

2(C) 

i 

MA) 

4(D) 

t 

g 

8 

9-8 

9 

s 

g-s 

g 

8 

g-s 

g 

s 

g-s 

Immediately 

after  mixing 

with  water. 

4.00 

1.20 

2.80 

1.24 

0.50 

0.74 

7.84 

2.94 

4.90 

8.30 

1.50 

6.80 

After  5  hrs. 

4.20 

1.60 

2.60 

2.30 

0.70 

1.60 

7.89 

3.02 

4.87 

— 

— 

— 

36  „ 

5.16 

1.96 

3.20 

3.12 

1.20 

1.92 

8.60 

3.68 

4.92 

9.56 

2.35 

7.21 

60  „ 

5.48 

2.02 

3.46 

3.80 

1.40 

2.40 

9.20 

4.35 

4.85 

— 

— 

— 

5  days 

6.24 

2.30 

3.94 

4.25 

2.20 

2.05 

9.80 

4.87 

4.93 

10.98 

3.88 

7.10 

8 

6.56 

2.58 

3.98 

4.40 

2.32 

2.08 

10.50 

5.60 

4.90 

— 

— 

— 

12 

6.90 

3.15 

3.75 

4.60 

2.40 

2.20 

11.04 

6.20 

4.84 

12.81 

4.66 

8.15 

20 

7.75 

3.84 

3.91 

5.48 

3.35 

2.13 

11.84 

6.56 

5.28 

14.60 

6.52 

8.08 

24 

7.80 

3.84 

3.96 

6.48 

4.02 

2.46 

11.60 

6.66 

4.94 

— 

— 

— 

40 

8.32 

4.11 

4.21 

7.06 

4.22 

2.84 

— 

— 

— 

— 

— 

— 

60 

9.02 

4.42 

4.60 

7.20 

4.18 

3.02 

— 

— 

— 

— 

— 

— 

HYDRATION   OF   PORTLAND   CEMENTS 


187 


TABLE  IV 


/i=2777.4 

fij_  =  2659.4 

M2=4585 

^3=4327 

1  (B) 

2(C) 

3  (A) 

4(D) 

t 

7 

cr 

y-<r 

7 

<r 

7-0- 

7 

0- 

y-a- 

7 

or 

7-<r 

Directly 

after  mixing 

with  water. 

6.17 

1.85 

4.32 

1.83 

0.73 

1.10 

19.97 

7.49 

12.48 

19.96 

3.60 

16.36 

After  5  hrs. 

6.48 

2.47 

4.01 

3.39 

1.03 

2.36 

20.10 

7.69 

12.41 







36  , 

7.96 

3.02 

4.94 

4.61 

1.77 

2.84 

21.91 

9.38 

12.53 

22.98 

5.65 

17.33 

60  , 

8.46 

3.11 

5.35 

5.61 

2.06 

3.54 

23.44 

11.08 

12.36 







5  days 

9.63 

3.54 

6.09 

6.28 

3.25 

3.03 

24.97 

12.40 

12.57 

26.39 

9.39 

17.06 

8 

10.12 

3.98 

6.14 

6.50 

3.43 

3.07 

26.75 

14.27 

12.48 







12 

10.65 

4.86 

5.79 

6.79 

3.54 

3.25 

28.13 

15.80 

12.33 

30.79 

11.20 

19.59 

20 

11.96 

5.92 

6.03 

8.09 

4.95 

3.14 

30.17 

16.71 

13.46 







24 

12.03 

5.93 

6.11 

9.57 

5.94 

3.63 

29.56 

16.97 

12.59 







40 

12.84 

6.34 

6.50 

10.43 

6.23 

4.20 













60 

13.92 

6.82 

7.10 

10.64 

6.17 

4.47 

— 

'  — 

— 

— 

— 

— 

A  comparison  of  the  figures  in  Tables  III  and  IV  shows  that  the 
hydration  phases  of  the  regenerated  hydraulite  (made  from  a  hardened 
cement  by  re-heating)  follow  each  other  more  rapidly  than  do  those  of 
the  original  cement.  From  this  it  may  be  concluded  that  the  hardened 
masses  were  not  properly  burned,  as  otherwise  the  hydration  phases 
in  the  regenerated  cement  would  occur  in  precisely  the  same  manner  as 
in  the  original  cement.  These  results  make  the  possibility  of  repro- 
ducing fresh  cement  from  hardened  masses  highly  probable. 

As  the  hydration  phases  follow  each  other  more  rapidly  than  in  the 
original  cement  (Tables  I  and  II)  a  much  lower  degree  of  hardness  must 
be  obtained  in  the  case  of  regenerated  cements  when  they  are  mixed 
with  water  and  allowed  to  set  and  harden .  This  was  actually  the  case  in 
Feichtinger's  experiments. 


Thermo-chemical  studies  of  hydration  and  hardening  processes  must 
lead,  in  the  case  of  cements  which  contain  free  lime,  to  results  which 
are  different  from  those  in  which  the  whole  of  the  lime  is  in  a  com- 
bined state. 

In  cements  of  the  former  kind  there  are  theoretical  reasons  why  a 
development  of  heat  must  occur  at  the  commencement  of  hydration 
(the  hydration  heat  of  the  CaO) ;  and  in  cements  devoid  of  free  lime  a 
perceptible  development  of  heat  can  only  occur  after  an  interval,  viz. 
at  the  moment  when  the  separation  and  hydration  of  the  first  CaO 
molecule  occurs. 

As  a  matter  of  fact,  Feichtinger  did  observe  a  noticeable  develop- 
ment of  heat  during  the  hydration  of  cement  4(D),  which  contains  free 
lime. 

In  this  connection  the  results  of  W.  Ostwald's  thermo-chemical 
studies  322  on  the  following  cements  are  particularly  interesting  : 


188 


CONSEQUENCES   OF  THE   H.P.   THEORY 


A     <UMO 


in^n     OTT  n 
0  Si02  •  2  H20 


Analysis  XII.* 
34MO 


31.5  CaO  •  2.5  MgO 

8 


Analysis  XXVIII. 
B.    92M0.6R2<V12Si02.3MgC0310H20   { 


SMgO 
3  =  5  A1203  -  Fe203. 


p     74.  Mn  .  a  p  n  .  i  A  Qin     <* 
C.     74  MO    6  R203    18  Si02  •  3 


Analysis  XXXI. 

Q  TT  n 
8  H0 


R  Q  = 


»O,. 


Analysis  XXXII. 

D.  76  MO  •  6  R203  •  18  Si02  •  MgC03  •  4  H20 

Analysis  XXXIII. 

E.  90  MO  -  6  R203  •  18  Si02  •  4  MgC03  •  10  H2O 

These  results  are  summarised  in  the  following  Table  : — 


Time 


D 


E 


2  hours 

7.53 

20.53 

9.94 

34.01 

20.47 

6      „ 

10.09 

37.05 

12.23 

35.46 

29.57 

1  day 

18.79 

41.35 

15.32 

38.39 

39.78 

4  days 

— 

46.16 

29.72 

— 

— 

5     ,, 

— 

47.17 

32.10 

— 

— 

6     „ 

— 

57.96 

33.56 

__ 

44.34 

7     „ 

— 

65.63 

40.21 

— 

51.55 

Ostwald  drew  attention  to  the  great  increase  in  heat  evolved  on  the 
5th,  6th  and  7th  days  and  suggested  that  after  this  time  a  new  stage  in 
the  hardening  process  occurs  and  is  accompanied  by  a  fresh  develop- 
ment of  heat.  This  noticeable  development  of  heat — for  which, 
hitherto,  no  satisfactory  explanation  has  been  given — is  readily  under- 
stood in  the  light  of  the  new  theory.  It  is  the  moment  of  hydration  of 
the  calcium  oxide  liberated  from  the  silicate  molecule. 

Further  references  to  the  development  of  heat  during  hardening  will  be  found  in 
the  Bibliography  under  No.  322. 

G 

As  the  most  important  hydraulic  limes  are  aluminosilicates,  it 
must,  theoretically,  be  possible  to  observe  the  conversion  of  primary 
into  secondary  types  by  the  action  of  alkaline  solutions  of  definite 
concentration.  This  deduction  has  been  confirmed  by  some  experi- 
mental results  obtained  by  Feichtinger323.  He  treated  the  hydraulic 
mortars  A,  B,  C  and  D  (both  in  the  fresh  state  and  after  they  had  been 
allowed  to  harden  for  some  time)with  aqueous  solutions  of  sodium  and 
potassium  carbonates,  and  allowed  these  reagents  to  act  for  some  time. 


*  For  the  analytical  figures,   see  the  corresponding  numbers  in  the  section  on 
Portland  cements  in  the  Appendix. 


ACTION   OF   ACIDS   AND   ALKALIES   ON   CEMENTS     189 

A  definite  quantity  of  silica  and  a  little  alumina  was  dissolved,  the 
amounts  being  expressed  in  percentages  and  molecules  in  the  following 
Table  : 

TABLE    V 


%  Si02 

Molecules  SiO2 

A 

B 

C 

D 

A 

B 

C 

D 

In  fresh  state    . 
After  14  days    . 
,,       3  months 
„       5     „        . 

2.63 
1.66 
1.42 
1.04 

5.09 
3.72 
2.50 
2.10 

6.78 
6.05 
5.80 
5.26 

4.24 
2.86 
2.40 
2.12 

2.17 
1.34 
1.14 

0.84 

4.11 
3.00 
2.02 
1.70 

2.98 
2.66 
2.55 
2.31 

2.13 
1.90 
1.82 
1.65 

From  this  Table  it  may  be  seen  that  the  Portland  cement  A  is  a 
basic  salt  of  the  type 

Si  •  M  •  SAi  •  Al  •  Si 

and,  in  the  fresh  state,  parts  with  2  mols.  Si02,  forming 

ST-Al-Sl-Al-Si. 

Similarly,  the  alkaline  solution  reacts  on  the  hydraulic  lime  D, 
which  is  a  compound  of  the  type 

Si  •  Al  -  SAi  -  M  -  Si. 
It  forms  a  compound  of  the  type 

ST-Al-Si-Al-ST, 

and  it  is  interesting  to  note  that  the  cements  B  and  C,  which  are  both 
basic  salts  of  the  type, 

/SI 

Al^ST 

XSi 

do  not,  when  in  the  fresh  state,  part  with  the  same  number  of  mole- 
cules. 

From  B — with  the  liberation  of  4  mols.  Si02 — a  compound 

Si-Al-Si-Si-Al-Si, 
and  from  C  a  salt  of  the  anhydride 

SAi  -  Al  -  Si, 

are  produced.  The  last-named  shows  that  hexa-compounds  may,  in 
some  cases,  be  produced  by  the  action  of  alkalies  on  penta-com- 
pounds. 

Table  V  also  shows  that  the  solubility  of  the  silica  diminishes  as 
the  cement  mass  hardens.  This  fact  is  also  in  agreement  with  the 
theory,  according  to  which  a  separation  of  CaO  from  the  hydraulites 
A,  B,  C  and  D  should  occur  and  the  combination  between  the  alumina 
and  silica  radicles  should  be  intensified. 


190 


CONSEQUENCES  OF  THE   H.P.   THEORY 


H 

The  separation  of  CaO  in  hydraulic  binding  materials,  which  is  a 
result  of  the  action  of  dilute  hydrochloric,  sulphuric,  carbonic  and  other 
acids,  of  alkaline  carbonates  or,  in  some  cases,  of  water  alone  (Portland 
cements),  must  take  place  in  accordance  with  certain  definite  stoichio- 
metrical  laws.  Valuable  contributions  to  the  support  of  this  statement 
have  been  made  by  Feichtinger324  and  Schott325. 

Feichtinger  has  studied  the  action  of  water  containing  carbonic 
acid  on  the  cements  1(B),  2(0),  3  (A),  4(D)  and  also  on  the  silicates  : 


=3C 


24  CaO  •  3  K203  •  15  Si02  •  2*  24  CaO  •  3  R2O3  •  12  Si02  -  2  f 

Analysis  XX,  Appendix.  Analysis  I,  Appendix. 

5  (E).  6  (F). 

Feichtinger's  object  was  to  discover  whether  the  whole  of  the  lime 
in  the  hardened  material  could,  in  this  way,  be  converted  into  calcium 
carbonate  or  whether  this  conversion  was  confined  to  a  portion  of  the 
lime.  Although  he  allowed  CO 2- water  to  act  on  the  hardened  material 
for  1 J  years,  he  was  unable  to  convert  the  whole  of  the  lime  into  CaC03 ; 
a  part  of  the  lime  remained  combined  with  the  silica.  Unfortunately, 
Feichtinger  did  not  publish  the  data  on  which  he  bases  his  conclusions 
regarding  the  proportions  of  lime  in  the  free  and  combined  state  after 
1J  years.  The  following  Table  shows  the  progress  of  the  decom- 
position, studied  by  Feichtinger,  during  only  5  months  : 

TABLE  VI 


Conditions  of  Experiments 

Percentage  of  CO2 

A 

B 

The  mortar  lay  3  months  in  clean  wate 
After  this  for  1  month  in  CO2-water 
„          2  months       „         „ 
»»           »»         »> 
••         »          *         »>           »         »> 
5 

p 

4.2 
14.4 
16.7 
18.2 
20.8 
20.9 

8.1 
16.3 
19.2 
19.4 
19.4 
19.4 

*  2  =  4  RCO8  +  0.25  Na2SO4  +  2  H2O. 

3  R,O3  =  1.5  A12OS  •  1.5  Fe2O3. 

4  RCO3  =  2.5  CaCO3  •  1.5  MgCO3. 
1 2  =  3  RCO3  +  0.5  R2SO4  +  2  H2O. 

3  RaO3  =  1.5  A12O3  •  1.5  Fe3O3. 
3  RCO3  =  2  CaC03  •  MgCO3. 


ACTION   OF   ACIDS   AND   ALKALIES   ON    CEMENTS     191 

TABLE  VII 


lli 


eS  fl 

II 


41.36 
38.12 
37.48 
39.56 
43.84 
41.13 


40.90 
36.13 
37.10 
36.80 
42.30 
41.70 


22.5 
19.4 
21.2 
21.3 
20.9 
24.0 


16 
12 
16 
15 

26 

27 


24 
21 
22 
24 
44 
26 


8 

9 

6 

9 

18 

12 


23.45 
19.30 
21.59 
22.29 
22.27 
23.14 


2860.8 
2777.4 
2659.4 
3090.9 
4585.0 
4327.0 


0 
0 
0 
0 
0 
13 


19.0 
14.5 
16.5 
19.0 
29.0 
29.0 


Table  VII  is  of  special  value,  as  it  allows  the  inference  that  the 
following  products  have  been  formed  by  the  action  of  carbonic  acid  on 
the  hydraulites  F,  B,  C,  E,  A  and  D  : 


1 


8CaO-3Al203-12SiOs 
F. 


9CaO-3Al2O3-15Si02 
B  and  E. 


6CaO-3Al203-15Si02. 
C.  ' 


=  1 


18  CaO  •  5  A1203  •  18  SiOs 
A. 


12  CaO  •  6  A120£ 
D. 


1 

18  Si02 


A  glance  at  the  above  structural  formulae  shows  that  the  separation 
of  CaO  must  be  in  accordance  with  quite  definite  laws.  Hence  it 
follows  from  the  structural  formulae  A  and  D  that : 

1.  The  lime  is  combined  more  strongly  with  the  middle  hexite  and 
cannot  be  so  easily  separated  as  it  can  from  the  side  hexites,  and 


192 


CONSEQUENCES   OF  THE   H.P.    THEORY 


2.  In  the  neighbouring  positions  2  and  3,  the  lime  is  more  feebly 
bound  than  in  the  positions  1  and  4. 

It  appears  to  be  unlikely  that  the  2°  side-chains  in  the  compound 
A  are  in  neighbouring  positions  (2,  3). 

A  comparison  of  the  structural  formulae  B,  C  and  E  shows  that  the 
lime  in  positions  1  and  3  in  the  pentites  is  more  strongly  combined  than 
in  position  2.  The  possibility  that  the  lime  in  C  forms  a  2°  side-chain 
in  position  2  is  improbable. 

Schott326  studied  the  reaction  of  a  cement  : 

42  CaO  •  3  R203  •  15  SiO,  •  2*. 


Molecular  Weight=3974.4 
G. 

137.4  parts  of  cement  hardened  by  (NH4)2CO3  gave  : 

CaC03  MgC03  CaS04   CaO    Fe203    A1203    Si02    H20     Insol.  Total. 

79.20       2.90      1.30     15.10    4.30      4.50     22.70   6.10       1.30  137.40 

57.56       2.10      0.98     10.99     3.14      3.28     16.53    4.44      0.98  100.00% 

These  results  lead  to  the  formula  : 

11  CaO  Fe203  2  A1203  15  SiO2  31  CaC03  1.5  MgC03  0.5  CaS04  14  H2O 


Calcd.   11.34 
Found  10.99 


2.95 
3.14 


3.75 
3.28 


16.68 
16.53 


57.06 
57.56 


2.32 
2.10 


1.25  4.64 
0.98  4.44 
0.98  (Insol.) 


(9H20 
+  32.5  RC03  - 


^  (1) 
OH          OH 

9  CaO  •  3  R203  •  15  Si02) 
2  Ca(OH)2  +  3  H2O  +  0.5  CaS04 
H. 


2.5  RCO8  •  0.5  CaSO4  •  2  H2O. 

2.5  KC03  =  1.5  MgCOs  +  0.5  K.CO,  +  0.5  Na2CO8. 

3  B2OS  =  2  A12O3  •  Fe2O8. 


PROGNOSES  RELATING  TO   CEMENTS  193 

The  structural  formula  H  suggests  a  comparison  with  the  formula 
B  previously  given.  The  decomposition,  so  far  as  the  separation  of 
lime  is  concerned,  occurs  in  a  similar  manner  ;  this  can  scarcely  be  a 
mere  coincidence. 

More  hydration  phases  occur  under  the  action  of  alkaline  carbonates 
of  certain  concentration  than  with  water  alone.  Hence,  in  such  cases, 
the  cement  masses  must  attain  a  greater  hardness,  as  Schott  has  shown 
experimentally. 

It  is,  therefore,  very  important  to  ascertain  the  nature  of  the 
action  of  carbonic  acid  on  hardened  mortar,  as  a  clear  conception  of  the 
changes  which  occur  to  cement  mortars  hardening  in  air  may  then  be 
obtained.  The  secondary  hardening  of  cements  allowed  to  set  in  air 
must  be  chiefly  referred  to  the  action  of  carbon  dioxide  and  moisture 
in  the  air. 

As  the  cement  mortar,  in  such  a  case,  undergoes  a  large  number  of 
hydration  phases  which  follow  each  other  very  slowly,  storing  in  air 
ought  to  give  a  harder  product  than  is  obtained  by  storage  underwater. 

J 

In  a  hydraulite  of  the  composition 

5°  5° 

II  II 

4°=/\/\/\==4° 

4oJSi|^Al|SiJ=4C 

'\/ 

5° 

it  is  possible  to  remove  a  portion  of  the  lime  by  means  of  hydrochloric, 
carbonic  or  other  dilute  acids,  or  of  dilute  ammonium  carbonate 
solution.  The  following  compounds  may  be  produced  in  this  manner  : 

3°  3° 

II  II 

CJSi|  Al|Si]^3o     2oII|Si|Al   Si  C2o  etc. 


1.  2.  3. 

These  compounds  may,  in  the  presence  of  water  or  dilute  alkalies, 
undergo  a  series  of  hydration  phases.  Hence,  if  a  portion  of  the  lime 
is  removed  from  combination  with  the  cement  by  means  of  dilute  acids, 
it  must,  to  a  certain  extent,  retain  its  hydraulic  properties. 

Fremy327  has  experimentally  removed  a  portion  of  the  lime  from 
hydraulic  limes,  and  has  treated  the  residue  with  dissolved  lime,  with 
the  result  that  the  mixture  hardened.  Zulkowski328  repeated  Fremy 's 
experiment,  and  found  that  as  much  as  14  per  cent,  may  be  removed 
from  some  Portland  cements  without  destroying  the  power  of  the 
residue  to  harden  when  mixed  with  water. 


194  CONSEQUENCES   OF  THE   H.P.   THEORY 

Such  hydraulites  as 


I  Si  |  Al  |  Al  |  Si 


cannot  contain  more  than  8  molecules  of  silicate-water,  but,  in  addition 
to  this,  A  can  have  a  theoretical  maximum  of  20  Ca(OH)2,  or  20  H20 
which  is  driven  off  at  a  red  heat.  B,  under  similar  circumstances, 
cannot  have  more  than  16  mols.  Ca(OH)2,  or  16  H2O  volatilised  at  a 
red  heat.  In  other  words,  there  is  for  each  cement  molecule  a  maximum 
proportion  of  silicate-water  and  of  calcium  hydroxide  water.  This 
statement  is  also  true  of  all  analogously  constituted  silicate  cements. 

It  will  be  interesting  to  observe  how  far  this  inference  from  the 
theory  is  supported  by  the  facts. 


If  a  hardened  mass  of  cement  containing  free  basic  lime-salts  is 
crushed,  it  will  harden  into  a  stony  mass  if  mixed  with  a  suitable 
quantity  of  water  or  dilute  solution  of  alkali.  These  lime-salts  are 
particularly  likely  to  be  present  where  hydration  is  effected  by  the 
action  of  alkali-free  or  acid-free  water.  As  the  number  of  hydration 
phases  in  such  partially  decomposed  silicates  is  large,  especially  in  the 
presence  of  a  little  alkali  and  water,  it  should  be  possible  to  produce 
materials  or  articles  of  great  hardness  from  such  silicates. 

Schott329  has  experimentally  obtained  a  second  setting  and  harden- 
ing by  mixing  a  pulverised  hardened  cement  mass  with  water. 

M 

As  the  bond  between  the  aluminium  hexite  and  the  silicon  hexites  is 
weakened  by  heating  aluminosilicates  and  by  their  combination  with 
lime,  it  should  be  possible  to  observe  that  when  the  material  is  treated 
with  dilute  acids,  a  separation  of  lime  and  of  gelatinous  silica  occurs,  as 
in  clays  (p.  107). 

This  is  actually  the  case,  and  Fuchs  made  this  fact  the  basis  of 
his  cement  theory. 

N 

If  hydraulic  limes  are  treated  with  concentrated  hydrochloric, 
sulphuric,  or  other  acids,  it  should  be  possible  to  observe  a  decom- 
position of  the  silicate  molecule  in  addition  to  the  separation  of  the 


PORTLAND  CEMENTS  AND   SEA  WATER  195 

lime.     The  silicate  molecules,  being  derivatives  of  clays,  must  be 
resolved  into  compounds  of  the  type 

SAi-Al-Al-sX    Si-Al-Al-Sl,  or    sVAT-H-Si 

(see  p.  107). 

So  far  as  the  authors  are  aware,  no  experiments  to  prove  this  have 
yet  been  made. 

0 

From  the  theory,  the  possible  existence  of  isomers  of  the  silicate 
cements  may  also  be  inferred.    Thus  the  compounds 


are  isomeric.    Up  to  the  present  these  isomers  have  not  been  investi- 
gated. 


Good  hydraulites  ought  only  to  be  producible  by  mixing  hydro- 
aluminosilicates  (clays)  with  limestone  or  chalk  in  theoretical  stoichio- 
metric  proportions,  the  ash  of  the  fuel  (alumina,  silica,  lime  and  alkali) 
used  being  also  taken  into  consideration. 

As  a  matter  of  experience  it  is  well  known  that  for  each  mixture 
only  definite  proportions  of  clay  and  lime  can  be  used  to  produce  good 
cements.  These  proportions  are  usually  found  empirically,  but  the 
formulae  given  by  the  authors  show  that  these  empirical  proportions 
agree  with  the  ones  theoretically  the  most  suitable  and  that  the 
empirical  proportions  are  scientifically  correct. 


Q 

A  New  Investigation  of  the  Sea  Water  Question 

Schuljatschenko330  correctly  states  that  it  is  very  difficult 
to  ascertain  accurately  the  cause  of  the  destruction  of  masonry 
exposed  to  the  action  of  the  sea ;  i.e.  whether  it  is  due  to  the  pro- 
perties of  the  bonding  material  (cement),  to  external  influences  such 
as  sand,  to  incorrect  proportions  of  the  materials  used  in  the  concrete, 
to  the  porosity  or  to  the  low  density  of  the  cement  blocks,  etc.  There 
can  be  no  doubt  that  all  these  factors  have  some  influence,  but  the  facts 
seem  to  show  that,  in  many  cases,  the  chief  cause  of  the  decomposition 
of  maritime  masonry  is  the  action  of  sulphur  compounds.  That  this 
inference  is  generally  true  is  shown  by  the  fact  that  a  large  number  of 


196  CONSEQUENCES   OF  THE   H.P.   THEORY 

investigators  have,  for  many  years,  endeavoured  to  ascertain  what 
substances  are  formed  by  the  action  of  calcium  sulphate  on 
cements. 

It  is  generally  agreed  that  Portland  cements  contain  compounds  of 
lime  and  alumina,  and  Candelot331  and  Michaelis332  have  concluded 
that,  by  the  action  of  gypsum  or  plaster  of  Paris  on  hardened  cement 
masses,  certain  calcium  sulpho-aluminates  are  formed,  and  that  these 
are  one  of  the  causes  of  swelling  of  cements.  Schott333  also  investi- 
gated the  action  of  gypsum  (plaster  of  Paris)  on  normal  Portland 
cement  and  on  analogous  cements  in  which  the  alumina  is  replaced  by 
iron  oxide.  In  both  cases  he  noticed  that  decomposition  occurred,  so 
that  the  formation  of  a  calcium  sulpho-aluminate  or  sulpho-ferrate 
appears  to  be  probable.  Schott  did  not,  however,  agree  with  the 
investigators  just  named  that  the  swelling  action  of  gypsum  (plaster) 
is  due  to  the  formation  of  sulpho-aluminates  or  sulpho-ferrates.  Le 
Chatelier334,  on  the  contrary,  is  in  favour  of  the  formation  of  a  definite 
calcium  sulpho-aluminate  and,  like  Deval335,  endeavoured  to  ascertain 
the  action  of  various  sulphates  on  cements  containing  various  propor- 
tions of  alumina. 

Rebuffat336  also  found  that  there  is  a  number  of  different  calcium 
sulpho-aluminates.  He  doubted,  however,  whether  the  destruction  of 
maritime  masonry  could  be  referred  to  the  formation  of  these  com- 
pounds. Here  again,  it  should  be  noticed,  the  swelling  and  disinte- 
grating effects  which  occur  when  gypsum  (plaster)  is  present  in  the 
cement  were  also  attributed  to  the  last-named  substance.  The  chief 
description  of  the  disadvantages  of  sulphates  on  cements  is  that  of 
Schiffner337,  who  had  collected  a  number  of  instances  in  which  the 
decomposition  was  unquestionably  due  to  the  action  of  sulphur  com- 
pounds on  the  hardened  cement  masses.  Some  of  these  interesting 
examples  may  be  mentioned  here  : 

1.  In  the  walls  of  a  railway  tunnel,  the  effects  of  some  destructive 
action  were  observed.    The  mortar  came  out  of  the  joints  in  the  form 
of  a  milky  fluid  and  carried  with  it  all  the  sulphate,  so  that  the  cement 
was  considered  to  be  bad.    It  was  only  after  a  very  careful  examination 
that  it  was  found  that  the  overlying  rocks  contained  sulphurous  lignite 
which  became  oxidised  to  sulphates,  the  latter  causing  the  destruction 
of  the  cement. 

2.  In  a  concreted  gallery  in  a  mine  in  Alsace-Lorraine  the  walls 
became  moist  and  porous  in  parts.     The  greater  portion  of  the 
structure  was  in  exceptionally  good  condition,  so  that  it  was  im- 
possible to  blame  the  cement,  but  in  some  portions  boil-like  swellings 
appeared,   the   mortar   becoming   semi-fluid   and  the    joints    loose. 
A  closer  examination  showed  that  the  nature  of  the  water  in  the 
neighbourhood   of   the   gallery   contained   calcium   and   magnesium 
sulphates  in  sufficient  quantities  to  effect  a  partial  decomposition  of 
the  concrete. 

3.  According  to  Grauer,  cracks  and  characteristic  white  crystals 


PORTLAND  CEMENTS  AND  SEA   WATER  197 

appeared  in  the  joints  of  a  sewer  built  of  bricks  laid  in  cement.    In 
this  instance  the  sulphates  were  introduced  by  the  sewage. 

4.  According  to  Le  Chatelier,  defects  appeared  in  the  cement  used 
in  the  Paris  fortifications  because  this  was  quite  close  to  the  famous 
gypsum  beds.    In  this  instance  the  sulphuric  acid  in  the  cement  rose 
from  0.4  to  3.75  per  cent. 

5.  In  a  tunnel  near  Almeria  (Spain)  the  mortar  swelled  a  few 
months  after  it  had  been  finished.    The  sulphuric  acid  content  rose 
from  0.3  to  2.3  per  cent.     The  ground  water  contained  2  g.  calcium 
sulphate  and  1 J  g.  magnesium  sulphate  per  litre  (or  140  and  105  grams 
per  gallon  respectively). 

6.  A  railway  viaduct,  which  passed  through  a  clay  deposit  con- 
taining gypsum  and  through  gypsum  beds,  suffered  seriously  because 
the  drainage  water  was  saturated  with  gypsum. 

These  instances  are  sufficient  to  show  the  serious  action  of  sulphur 
compounds  on  cement,  and  the  question  arises  as  to  whether  any 
information  may  be  gained  from  a  study  of  the  constitution  of  the 
cements,  or  from  the  observations  and  experiments  which  have  been 
made,  whereby  this  action  may  be  explained,  and,  if  possible,  prevented. 
The  reader  may  be  surprised  to  learn  that  this  question  can  be  answered 
in  the  affirmative  in  the  following  manner  : 

If  water  is  allowed  to  act  on  a  typical  Portland  cement  such  as  : 

4°   OK  OK  4° 

II      I      I      II 


oo     f  01 1  Al   Al    Si  I     «c 
6  »kX    ~     A     '— * 


YY 

4°   OK 


KOK4° 
A. 

a  hard,  cement  mass  with  the  formula 

(2)  OH  OH  (2) 

I      I 


+  x  Ca(OH)2  +  2 

(2) 

B. 
is  formed. 

From  the  formula  B  it  may  be  seen  that  the  silicate  of  the  hardened 
cement  contains  a-hydrogen  (marked  with  a  +),  and  on  p.  140  it 
was  shown  that  the  a-hydrogen  tends  to  be  replaced  by  monovalent 
acid  radicles  such  as  — SO2  •  OH,  — SO  •  OH,  etc. 

In  this  manner  all  kinds  of  A-  and  Z-aluminosilicates  such  as  the 
ultramarines  (p.  140  et  seq.)  may  be  formed.  If  the  cement  mass  B 
comes  into  contact  with  solutions  of  salts  such  as  gypsum,  it  is  by  no 


198 


CONSEQUENCES   OF  THE   H.P.   THEORY 


means  improbable  that  2-aluminosilicates  will  be  formed.  High 
temperatures  are  unnecessary,  as  Thugutt  has  shown  that  the  formation 
of  the  2-aluminosilicates  (sodalites)  may  take  place  at  low  tempera- 
tures in  the  presence  of  solutions  of  suitable  salts.  As  the  formation 
of  these  substances  is  accompanied  by  a  change  in  volume,  it  is  clear 
that  the  hardened  cement,  such  as  B,  must  crack  if  its  hydrogen  is 
replaced  by  acids  or  acid  radicles  (p.  152)  and  that  it  may  be  completely 
destroyed. 

Hence  it  follows  that  the  authors'  cement  theory  permits  the 
prediction  that  the  action  of  sulphates  on  cement  will  be  accompanied 
by  disastrous  results.  The  possibility  of  the  disintegration  of  maritime 
masonry  by  the  action  of  the  sulphates  of  calcium,  magnesium,  etc.,  in 
the  sea  water  is  thereby  explained. 

There  now  remains  the  question  as  to  whether  this  serious  action  of 
sea  water  can  be,  in  any  way,  prevented.  In  cases  where  the  destruc- 
tion of  the  cement  work  is  exclusively  confined  to  the  action  of  the 
sea  water,  the  most  satisfactory  solution  of  the  problem  will  be  found 
in  the  use  of  cements  in  which  no  a-hydroxyls  can  be  formed,  i.e. 
cements  of  the  types  : 


AlSi, 
X 


All-Si       and     AU-S 


Si 


(p.  189) 


If  this  inference  from  the  theory  can  be  proved  experimentally — and 
the  practical  observations  and  experimental  results  previously  men- 
tioned almost  amount  to  such  a  proof — an  interesting  and  important 
practical  result  would  be  obtained  from  purely  theoretical  reasoning, 
and  would  form  a  notable  step  in  the  direction  of  a  solution  of  the 
"  sea- water  problem." 

R 

From  the  theory  it  follows  that,  from  clays  containing  a-hydroxyls, 
compounds  must  be  producible  which  contain  both  hydraulites  and  A- 
or  2-aluminates  or  ultramarines,  i.e.  pigments  with  hydraulic  pro- 
perties such  as  : 


CONSTITUTION   OF  THE  PORCELAIN  CEMENTS 

S 


199 


=  (2) 


etc. 


0         (2) 

SO,    S02 
ONa 


ON 


It  will  be  interesting  to  learn  whether  this  prognosis  can  be  proved 
by  the  actual  production  of  such  substances. 


XIV 
A  New  Theory  of  the  Silicate  or  Porcelain  Cements 

Certain  kinds  of  transparent  silicate  cements,  which  are  conveni- 
ently known  as  porcelain  cements,  have  been  used  for  some  years 
as  dental-stopping  materials.  The  first  of  these  porcelain  cements  was 
discovered  and  patented  in  1878  by  T.  Fletcher338,  but  it  did  not 
fulfil  his  anticipations  and  rapidly  fell  out  of  use.339  An  interval  of  25 
years  appears  to  have  elapsed  before  any  other  porcelain  cements  were 
produced,  and  these  were  of  a  different  composition.  Those  placed 
on  the  market  in  1904  by  Ascher  and  others  were  heartily  welcomed 
as  new  discoveries  in  dentistry,  and  they  rapidly  attained  great 
popularity  on  account  of  their  valuable  characteristics. 

It  may  be  here  pointed  out  that  the  porcelain  cements  appear 
likely  not  only  to  replace  the  zinc  phosphate  cements  and  amalgams, 
but  also  the  burned  enamels  and  the  "  queen  "  of  stoppings — gold — in 
practical  dentistry  !  Morgenstern  has  expressed  himself  as  follows 
respecting  these  new  stopping  materials  :  34°  "  Porcelain  cement,  when 
properly  selected  and  prepared,  sets  to  form  a  mass  with  a  remarkable 
resemblance  to  natural  teeth,  both  in  colour  and  transparency  and 
possessing  a  gloss  which  is  confusingly  like  that  of  natural  dentitic 
enamel.  These  stoppings  have  no  objectionable  features,  and  in  no 
way  harm  the  teeth,  and  they  have  a  great  advantage  over  gold  and 
the  burned  enamels  in  that  they  save  the  dentist  thousands  of  hours  of 
work  and  greatly  economise  his  health  and  power.  They  save  the 
patients  many  a  painful  hour  and  have  great  pecuniary  advantages." 

Porcelain  cements  consist  of  two  ingredients — a  powder  and  a  fluid. 
According  to  Sanderson,  Fletcher's  powder  was  composed  of  aluminium 
hydrate,  zinc  oxide  or  magnesia  and  a  basic  zinc  silicate.  The  powders 


200  CONSEQUENCES   OF  THE   H.P.   THEORY 

of  the  new  porcelain  cements  consist  chiefly  of  calcium  alumino- 
silicates. 

The  fluids  of  the  new  cements  differ  from  that  of  Fletcher  chiefly 
in  their  consistency.  Fletcher's  fluid  was  a  syrupy  solution  of  alu- 
minium phosphate  in  phosphoric  acid,  whilst  the  newer  ones  are  less 
syrupy  and  consist  chiefly  of  alumina  and  phosphoric  acid.  There  was, 
until  recently,  a  cement  of  which  the  powder  resembled  that  of  Fletcher 
and  consisted  chiefly  of  calcium  aluminosilicate  and  zinc  oxide.  The 
fluid  had  a  consistency  resembling  that  of  Fletcher's  fluid,  but  was 
chiefly  composed  of  alumina  and  phosphoric  acid  with  a  large  pro- 
portion of  zinc  oxide.  It  differed  from  Fletcher's  cement  because  it 
was  a  practicable,  dental-stopping  material. 

On  mixing  the  silicate  powder  with  the  fluid,  there  is  immediately 
formed  a  transparent  mass  which  is  at  first  plastic — in  distinction  from 
the  earlier  zinc  phosphate  dental  cements — but  rapidly  becomes  quite 
hard. 

The  powder  of  the  new  cements  contains  the  same  constituents  as 
the  Portland  and  slag  cements,  but  instead  of  the  fluid  being  pure  water 
or  alkaline  water,  acids  (aluminophosphoric  acids),  or  solutions  of  acid 
salts  (aluminophosphates),  are  employed. 

From  a  scientific  point  of  view  it  is  highly  important  that  an 
investigation  should  be  made  with  a  view  to  ascertaining  the  constitu- 
tion of  the  porcelain  cements  in  order  to  solve  a  number  of  physical 
and  chemical  problems  in  connection  with  their  setting.  This  investiga- 
tion appears  to  be  all  the  more  necessary  when  the  available  experi- 
mental results  and  the  theories  already  formulated  are  critically 
examined.  If  the  new  hexite  theory  proves  of  use  in  this  investigation, 
it  will  not  only  add  to  the  value  of  the  theory  itself,  but  will  clear  many 
problems  of  enormous  and  pressing  importance  in  surgery  and  particu- 
larly in  dentistry. 

The  ijew  silicate  cements — with  the  exception  of  those  containing 
a  large  proportion  of  zinc  oxide  both  in  the  powder  and  in  the  fluid 
portion — have  one  serious  drawback  :  they  have  a  destructive  action 
on  the  nerves  (pulpa)  of  the  teeth.  For  this  reason  there  has  long  been 
a  dispute  as  to  the  best  means  of  preventing  this  poisonous  action. 

In  regard  to  this  and  to  several  other  problems — e.g.  the  best 
methods  of  testing  the  durability,  density  and  hardness  of  such  cements, 
both  in  the  laboratory  and  in  the  mouth — much  remains  to  be  done. 
It  is,  however,  clear,  that  in  all  investigations  of  this  kind,  a  knowledge 
of  the  constitution  of  the  cements  and  of  the  changes  which  take  place 
during  their  setting,  must  be  of  the  greatest  importance. 

The  porcelain  cements  must  possess  a  number  of  very  definite 
characteristics,  such  as  unchangeableness  of  shape  and  size  in  the 
mouth,  resistance  to  the  action  of  saliva,  etc.,  if  they  are  to  fill  a  useful 
place  in  applied  dentistry. 

Miller341  considers  that  an  ideal  dental  stopping  should  have  the 
following  characteristics  : 


LABORATORY  TESTS   ON  PORCELAIN   CEMENTS      201 

1.  Sufficient  hardness  so  as  not  to  be  worn  away  unduly  by 
mechanical  forces  in  the  mouth. 

2.  Unchangeability  in  saliva,  food-stuffs  and  other  decomposition 
products  (chemical  indestructability). 

3.  Constancy  of  form  and  volume  when  placed  in  the  teeth. 

4.  Low  heat  conductivity,  so  that  any  changes  in  the  temperature 
of  the  mouth  are  not  transmitted  to  the  nerves  of  the  teeth. 

5.  A  high  degree  of  plasticity  in  order  that  the  stopping  may  be 
water-tight  and  may  properly  fit  the  teeth. 

6.  Colour  as  similar  as  possible  to  that  of  the  teeth. 

7.  Absence  of  detrimental  action  on  the  tooth  material,  nerves, 
mucous  membrane  and  the  general  health. 

8.  Easy  manipulation. 

9.  Minimum  sensitiveness  to  moisture. 

10.  Adhesiveness  to  the  tooth- wall. 

11.  Antiseptic,  at  any  rate  during  fitting. 

12.  Easy  removal,  if  necessary. 

The  possibility  of  producing  ideal  stopping  materials  depends 
chiefly  on  a  knowledge  of  the  chemical  constitution  and  on  a  clear 
understanding  of  the  reaction  which  occurs  during  the  hardening  of 
these  substances.  If  no  scientific  basis — no  scientifically  grounded 
theory — of  the  porcelain  cements  is  possible,  the  manufacturers  of 
these  substances  can  only  work  in  an  arbitrary  manner  in  attempting 
to  improve  the  quality.  To  do  this  is,  however,  risky,  as  it  is  possible 
that  some  manufacturers  may  even  produce  inferior  products  instead 
of  "  improvements  "  ;  the  final  material  may,  in  fact,  be  worse  than 
the  original  one,  though  it  may  be  sold  as  "  greatly  improved."  In 
one  case  a  porcelain  cement  was  so  much  "  improved  "  that  it  was 
eventually  agreed  that  the  material  made  five  years  previously  was  by 
far  the  "  best,"  and  the  manufacturers  were  obliged  to  forego  their 
"  improvements  "  and  to  use  the  older  recipe  ! 

A  large  amount  of  theoretical,  and  especially  of  experimental  work, 
has  been  done  in  connection  with  porcelain  cements,  but  it  cannot  be 
said  that  this  has  made  the  most  important  properties,  such  as  the 
poisonous  nature  of  some  of  these  cements,  more  comprehensible.  The 
solution  of  this  problem  of  poisoning — undoubtedly  one  of  the  most 
important — is  made  particularly  difficult  by  the  absence  of  any  well- 
established  theory,  and  even  more  serious  are  the  effects  of  false  and 
purely  speculative  theories  and  especially  of  wrong  explanations  and 
faulty  interpretations  of  experimental  results. 

In  this  connection  the  litmus  experiment  of  Rawitzer348  is  pecu- 
liarly typical.  This  investigator  endeavoured  to  show,  by  means  of 
strips  of  paper  soaked  in  blue  litmus  solution,  that  the  porcelain 
cements  containing  zinc  oxide  are  poisonous,  whereas  their  innocuous- 
ness  has  been  proved  by  laboratory  tests  and  is  obvious  from  a  study 
of  their  chemical  constitution.  Rawitzer  appears  to  have  overlooked 
the  fact  that  a  substance  may  turn  blue  litmus  red  and  yet  may  not  be 


202  CONSEQUENCES   OF  THE   H.P.   THEORY 

prejudicial  to  health  ;  it  all  depends  on  the  amount  of  acidity  present. 
A  substance  may  even  be  acid  and  yet  may  not  have  any  detrimental 
action  on  the  teeth.  For  instance,  concentrated  hydrochloric  acid  is 
unquestionably  a  violent  poison,  but  dilute  hydrochloric  acid  is,  on  the 
contrary,  an  internal  medicine  of  great  value.  Yet  both  solutions  turn 
blue  litmus  red  !  Litmus  alone  cannot  give  any  clue  as  to  the  amount 
of  acidity,  and  is,  therefore,  useless  for  determining  poisonous  qualities. 
Rawitzer  had  not,  apparently,  a  clear  view  of  the  meaning  of  the  term 
"  acid  reaction,"  and  was  but  partially  informed  with  regard  to  the 
structure  of  the  hardened  cement  masses  ;  consequently  he  had  an 
erroneous  idea  of  the  physico-chemical  reactions  occurring  during 
the  hardening. 

The  absence  of  more  definite  knowledge  of  the  nature  of  the 
porcelain  cements  has  led  to  several  false  and  meaningless  investiga- 
tions by  Dreschfeld342,  Strumpel343,  Robert  Richter344,  and  Kulka345. 
These  have  been  criticised  by  Schreiber346. 

For  instance,  Dreschfeld,  Strumpel  and  Richter347  digested  the  raw 
cement  (composed  of  a  solid  aluminosilicate  and  a  fluid  containing 
alumino-phosphoric  acid  and  aluminophosphate  of  zinc)  with  water 
for  various  periods  of  time.  According  to  the  length  of  this  digestion  a 
proportionate  quantity  of  the  uncombined  cement  would  be  decom- 
posed, the  result  being  a  partial  splitting  up  of  the  cement  mass  into  its 
components.  These  acid-reacting  decomposition  products  were  titrated 
and  regarded  as  "free  phosphoric  acid  "  by  the  investigators  named. 

Yet  what  is  the  use  of  showing  the  presence  of  acid  in  the 
decomposition  products  of  a  substance  which  is  known  to  have  an 
acid  as  one  of  its  original  constituents  ? 

The  same  authors  also  studied  the  action  of  freshly  mixed  (and 
therefore  uncombined)  cements  on  various  colourless  solutions  as  well 
as  solutions  of  aniline  dyes,  fruit  juices  (bilberry  juice),  etc.  They 
regarded  a  cement  which  produced  no  colour  in  the  presence  of  aniline 
dye-stuffs  as  perfect !  Yet  it  is  clear  that  even  the  "  densest  cement," 
in  a  fresh  (unhardened)  state,  must  necessarily  form  a  compound  of  an 
intense  colour  if  such  cements  form  a  lake  by  combining  with  the  dye- 
stuff.  It  is  a  well-known  fact  that  a  valuable  series  of  aniline  lakes  are 
produced  from  aluminosilicates  and  certain  basic  aniline  dye-stuffs  ;  is 
it  reasonable  to  suggest  that,  because  an  aluminosilicate  forms  a  lake 
with  a  certain  aniline  dye-stuff,  it  is,  therefore,  unsuitable  as  a  dental 
stopping  ? 

Kulka  falls  into  a  similar  error  in  his  experiments,  and  he  appears 
to  have  paid  no  attention  to  the  physico-chemical  reactions  of  harden- 
ing in  his  studies,  although  Morgenstern349  and  Schreiber350  had  called 
attention  to  them.  Morgenstern  was,  therefore,  induced  to  issue  a 
warning  in  regard  to  the  experiments  of  Kulka  and  to  the  general 
manner  in  which  investigations  on  silicate  cements  are  carried  out. 
In  this  warning  Schreiber  joined.  Both  these  authorities  believe  that 
it  may  be  safely  assumed  that  Kulka  would  never  have  carried  out 


LABORATORY  TESTS   ON   PORCELAIN   CEMENTS     203 

his  experiments  on  imperfectly  hardened  cements  if  he  had  been  clear  as 
to  the  constitution  of  these  substances  and  the  changes  in  their  physical 
and  chemical  properties  which  occur  during  the  different  hardening 
phases. 

As  Morgenstern351  rightly  says  :  "  It  is  incorrect  to  stop  the  various 
chemical  and  mechanical  processes  in  cements  prepared  for  experi- 
mental purposes  before  the  hardening  is  complete.  The  cements  so 
treated  lose  very  valuable  properties  and  lead  to  erroneous  results. 

"  If  this  were  a  matter  of  purely  theoretical  or  academic  interest  I 
should  not  write  about  it,  but  would  modestly  express  my  contrary 
opinion.  This  is,  however,  a  case  where  the  conclusions  are  of  great 
practical  and  technical  importance,  and  Kulka's  theories  may  have  a 
most  important  influence  on  the  use  of  silicate  cements  in  dentistry  and 
on  their  production  by  the  manufacturers.  It  is  because  I  am  con- 
vinced that  this  influence  may  be  profitless  and  even  harmful  that  I 
feel  right  to  call  '  Halt ! '  to  those  colleagues  who  are  following  these 
new  paths." 

Morgenstern  himself  treated  the  cements  with  chemical  agents  from 
half  to  three  hours  after  hardening.  He  agrees,  however,  that  he  could 
not,  in  this  way,  definitely  ascertain  the  true  properties  of  the  cements 
he  examined  :  "I  treated,"  he  says,352  "  my  cements  with  water  at 
35°  C.  for  one-half  to  three  hours,  and  found  that  their  adhesion, 
durability,  density  and  resistance  to  acids  and  alkalies  were  such  that 
the  results  obtained  cannot  be  regarded  as  showing  the  inherent  good 
characteristics  or  their  value  as  dental  stoppings." 

Morgenstern353  rightly  says  that  in  many  of  his  experiments  Kulka 
paid  too  little  attention  to  the  time  required  for  hardening  the  cements  : 
"  Before  commencing  his  special  experiments,  he  (Kulka)  treated  his 
cement  fillings  (30  minutes  after  they  had  set)  with  a  mixture  of  saliva 
and  water  and  allowed  them  to  remain  in  it  for  seven  days,  the  fluid  being 
renewed  occasionally.  He  found  that  some  cements  showed  no  change, 
others  a  little  change,  and  others  again  were  much  altered,  and  that  one 
cement  was  completely  destroyed.  These  changes  in  structure  and 
hardness  are  good  evidence  that  the  different  cements  take  different 
times  to  complete  hardening." 

As  Kulka,  in  his  researches,  did  not  pay  any  attention  to  the 
hardening  phases  in  his  cements,  he  found,  as  Morgenstern  has  shown, 
that  as  great  a  loss  of  material  occurred  when  the  cement  was  treated 
with  a  0.5  per  cent,  solution  of  lactic  acid  as  is  only  produced  in  three 
weeks  in  a  properly  hardened  cement. 

Schreiber354  has  pointed  out  the  interesting  fact  that  Kulka's 
phosphate  cements  possessed  no  adhesion,  so  that  Kulka's  conclusions 
—based  on  too  early  a  treatment  of  the  cements  with  saliva,  i.e.  before 
they  had  properly  hardened — must,  necessarily,  be  erroneous.  As  a 
matter  of  fact,  Kulka  covered  the  ends  of  small  pieces  of  ivory  with 
cement,  and  after  an  hour's  standing  placed  them  in  saliva- water,  where 
they  remained  for  six  days.  At  the  end  of  this  period  he  found  "  to  his 


204  CONSEQUENCES   OF  THE   H.P.   THEORY 

astonishment  "  that  the  ivory  could  be  completely  withdrawn  from 
the  cement  covering  with  comparative  ease.  From  this  experiment 
Kulka  drew  his  erroneous  conclusions. 

Another  serious  omission  in  the  records  of  experiments  mentioned 
on  the  last  two  pages  is  that  none  of  the  investigators  named  mentions 
the  proportion  of  powder  to  fluid  which  he  used  in  his  tests.  Hence  it 
is  not  difficult  to  understand  that,  as  Schreiber355  has  shown,  under 
apparently  identical  conditions  a  cement  mass  x  is,  according  to  one 
investigator,  only  ^ih  as  resistant  as  the  mass  y  ;  according  to  another 
investigator  it  is  only  Jth  as  resistant  as  the  same  mass  y  ;  according 
to  a  third  it  has  the  same  resistance  to  acids  as  y,  and,  finally,  a  fourth 
reports  it  as  being  more  resistant  than  y  !  Clearly,  these  different  men 
have  worked  with  cements  of  widely  differing  degrees  of  hardness  and 
therefore  with  very  different  proportions  of  powder  to  fluid.  Schreiber 
has  correctly  stated,  in  regard  to  this  remarkable  result  of  the  study 
of  these  experiments  with  silicate  cements  :  "  Are  not  these  results 
significant  ?  Can  any  reliance  be  placed  on  experiments  which  give 
such  contradictory  results  ?  It  is  impossible  to  believe  that  any 
substance  can  behave  so  differently  in  analogous  experiments." 

In  spite  of  Morgenstern's  warning  and  Schreiber's  severe  criticism, 
Kulka  has  continued  to  pay  no  attention  to  the  hardening  phases  and 
other  important  properties  of  the  silicate  cements.  In  his  latest  work 
—  on  the  possibility  of  chemical  and  pathological  actions  of  cement 
stoppings356  —  he  endeavours  to  determine  the  acidity  of  various 
silicate  masses  shortly  after  they  have  been  produced,  i.e.  during  the 
first  stages  of  hardening.  This  is  a  very  important  problem  ;  yet  how 
does  Kulka  attempt  its  solution  ?  He  mixes  the  powder  with  the  fluid 
and,  either  at  once  or  after  20  to  40  minutes,  during  which  the  mass 
is  kept  at  a  temperature  of  35°,  he  grinds  it  to  a  fine  powder.  He  then 
treats  about  1  g.  of  this  powder  with  150c.c.  distilled  water  for  24  to 
48  hours.  At  the  end  of  this  period  the  powder  is  removed  by  filtration 

and  the  liquid  titrated  with  rr  potassium    hydrate.      The    alkali 


neutralised  is  expressed  in  terms  of  "  free  phosphoric  acid." 

A  further  study  of  this  so-called  "  quantitative  determination  "  of 
the  **  free  phosphoric  acid  "  shows  that  this  method  is  not  merely 
objectionable,  but  is  entirely  erroneous  because  : 

1.  By  adding  a  larger  quantity  of  water  to  the  finely  powdered 
but  unhardened  cement  mass,  and  especially  if  it  is  also  stirred  con- 
tinuously for  24  to  48  hours,  not  only  is  the  cement  decomposed,  but, 
in  the  case  of  cements  in  which  the  fluid  is  a  solution  of  zinc  salts, 
these  salts  separate  out  as  new  constituents  !  Acid  decomposition 
products  of  the  most  varied  nature  enter  partially  into  solution.  On 
titrating  the  filtrate  —  assuming  that  it  can  be  titrated  (see  2  below)  — 
what  is  really  determined  is  the  proportion  of  substances  which  are,  to 
a  large  extent,  of  secondary  origin  and  are  not  contained  in  the  original 
material  ! 


CRITICISM   OF  EXISTING   THEORIES  205 

2.  It  is  entirely  wrong  in  principle  to  titrate  acid-reacting  solutions 
of  metallic  salts  (zinc  salts  of  aluminophosphoric  acid)  and  to  determine 
the   "  free  acid  "  by  means  of  the  amount  of  potassium  hydrate 
required,  because  many  solutions  of  metallic  salts  react  like  acids,  but 
contain  no  trace  of  free  acid.    Copper  sulphate,  cobalt  chloride,  nickel 
sulphate,  etc.,  are  typical  in  this  respect. 

3.  None  of  the  fluid  portions  of  silicate  cements  contained  free 
phosphoric  acid,  but  phosphoric  acid  combined  with  alumina,  i.e. 
aluminophosphoric  acid  and  their  zinc  salts. 

These  complex  aluminophosphoric  acids  and  their  salts  have 
entirely  different  chemical  and  physiological  properties  from  those  of 
free  phosphoric  acid  and  must  not  be  confused  with  it.  This  is  the  more 
important  as  the  alumina,  as  will  be  shown  later,  plays  a  very  important 
part  in  the  physiologico-chemical  action  of  these  acids. 

Yet  Kulka,  in  his  determination  of  the  "  free  acid,"  entirely  over- 
looks this  alumina  and  regards  the  cement  fluid  as  consisting  of 
"  orthophosphoric  acid  "  in  which  one  atom  of  hydrogen  has  been 
replaced  by  a  base.  This  view  is  quite  erroneous  and  unfounded. 

Under  these  conditions  it  is  not  surprising  that  Kulka's  "  deter- 
minations of  acidity,"  in  various  silicate  masses,  led  him  to  regard 
what  are  known  in  practice  as  highly  poisonous  cements  as  "  harmless  " 
and  those  which  are  entirely  free  from  danger  as  "  the  most  poisonous." 

From  the  experiments  of  Morgenstern,  Kulka  and  others  it  was 
discovered  that  the  porcelain  cements  have  a  far  higher  resistance  to 
acids  than  have  ivory357  and  the  enamel  of  natural  teeth.358 

This  fact  is  of  special  importance  inasmuch  as  it  provides  the  key 
to  the  constitution  of  the  silicate  cements.  It  is  also  important  to 
observe  that  some  of  these  cements  possess  this  high  resistance  even 
before  they  are  fully  hardened  !  This  fact  also  provides  means  for 
studying  the  course  of  reactions  which  occur  during  the  hardening  and 
in  this  way  excludes  a  priori  a  number  of  hypotheses  which  will  be 
mentioned  presently. 

Critical  Examination  of  various  Hypotheses  concerning  the  Course  of 
Reaction  during  the  Hardening  of  the  Porcelain  Cements 

Experimental  results  are  available  from  which  it  is  possible  to 
learn  the  course  of  the  chemical  reactions  which  occur  in  the  hardening 
of  porcelain  cements.  It  is  clear  that  so  long  as  no  scientific  and  well- 
founded  theory  was  put  forward,  these  results  must  remain  in  the 
background.  Several  of  these  hypotheses  must,  however,  be  aban- 
doned, if  the  high  resistance  of  the  half -hardened  cement  to  acids  is  to 
be  taken  into  consideration. 

Jung359  was  one  of  the  first  to  endeavour  to  explain  the  chemical 
changes  which  result  in  the  hardening  of  the  porcelain  cements.  He 
first  assumed  that  the  powders  are  "  chemical  compounds  of  silica, 
alumina,  lime,"  etc.,  but  found  an  "important  error"  in  the  com- 
position of  these  cements  and  was  led  to  conclude  that,  on  mixing  the 


206  CONSEQUENCES   OF  THE   H.P.   THEORY 

powder  with  the  fluid,  a  separation  of  lime  and  magnesia  in  the  form 
of  calcium  and  magnesium  phosphate — i.e.  a  separation  of  readily 
soluble  substances — must  occur.  "  The  solubility  of  these  substances 
in  acids,"  says  Jung,  "  may  be  reduced  by  the  admixture  of  alumina, 
silica,  etc.,  but  it  can  never  be  removed  altogether." 

The  proved  slight  solubility  of  the  porcelain  cements  in  acids  is 
clearly  opposed  to  the  separation  of  lime  and  magnesia  as  just  sug- 
gested. 

Morgenstern360  also  appears  to  have  discovered  the  same  "  import- 
ant error  "  as  Jung.  "  We  know,"  he  says,  "  that  the  general  chemical 
composition  of  the  cements  is  due  to  their  calcium  and  magnesium 
contents,  and  that  the  reaction  between  the  powder  and  the  fluid 
results  in  the  formation  of  calcium  and  magnesium  phosphates,  which 
are  known  to  be  readily  soluble  in  acids.  This  naturally  leads  us  to 
fear  that  dental  stoppings  made  of  such  cements  cannot  have  much 
resistance  to  the  acids  present  in  the  human  mouth . ' '  Yet  Morgenstern 
has,  himself,  shown  the  great  resistance  of  these  cements  to  acids,  and 
has  further  demonstrated  that  the  reactions  which  take  place  during 
hardening  must  be  different  from  those  mentioned  in  the  above 
quotation.357'358 

Kulka361,  in  1909,  published  a  theory  concerning  the  chemical 
reactions  occurring  during  the  hardening  of  porcelain  cements,  accord- 
ing to  which  the  action  of  the  acid  on  the  powder  produces  successively 
primary,  secondary  and  tertiary  calcium  phosphates.  This  theory  is, 
however,  opposed  to  the  resistance  of  the  silicate  masses  to  acids 
which  Kulka  has,  himself,  proved  1 

Schreiber362  has  severely  criticised  Kulka's  theory,  and  has  rightly 
demanded  that  any  theory  of  the  hardening  of  a  cement  must  neces- 
sarily explain  why  the  calcium  compounds  produced  do  harden. 
Any  theory  to  be  satisfactory  must,  for  example,  explain  why  a  cement 
fluid  which  has  been  diluted  with  water  effects  a  more  rapid  hardening 
than  the  concentrated  fluid,  and  so  forth.  For  this  fact  the  Kulka 
theory  affords  no  explanation. 

Rawitzer363  has  also  attempted  to  explain  the  course  of  the  re- 
actions which  produce  a  hardening  of  the  porcelain  cements  ;  but  his 
suggestion  that  the  phosphoric  acid  in  the  cement  fluid  causes  the 
precipitation  of  the  whole  of  the  silica  in  the  aluminosilicate  powder 
in  an  insoluble  form  is  directly  opposed  to  general  experience  with 
regard  to  the  behaviour  of  aluminosilicates.  Moreover,  silica  pre- 
cipitated in  an  insoluble  form  from  aluminosilicates  must  usually  be  in 
the  form  of  a  gelatinous  mass,  yet  in  porcelain  cements  this  form  is  not 
produced. 

Somewhat  more  noteworthy  is  the  hardening  theory  suggested  by 
Apfelstadt364,  who  considers  the  powder  to  be  composed  of  a  mixture  of 
alumina  and  clay.  On  mixing  this  powder  with  the  fluid,  the  alumina 
combines  with  the  "free  phosphoric  acid"  in  the  latter,  A12(P04)2 
being  precipitated.  This  precipitate  "  cements  the  previously  formed 


ARE   PORCELAIN   CEMENTS   MIXTURES?  207 

aluminium  phosphate  and  the  clay  substance  together."  This  investi- 
gator also  attributes  the  poisonous  action  of  the  silicate  cements  to 
the  presence  of  "  free  phosphoric  acid."  His  theory  affords  no  explana- 
tion of  the  great  resistance  of  the  fully  hardened  cements  to  acids. 
It  is  well  known  that  clay  substance  is  resistant  to  acids,  yet  the 
alumina  and  the  "  cemented  aluminium  phosphate  "  must  be  readily 
soluble  in  acids.  What,  also,  is  to  be  said  about  the  lime  and  mag- 
nesia ?  To  this  question,  Apfelstadt's  theory  affords  no  answer. 
Moreover,  the  expression  "  cemented  "  is  by  no  means  a  clear  one. 
In  short,  Apfelstadt  gives  no  satisfactory  explanation  of  hardening, 
and  his  opinion  that  porcelain  cements  are  mixtures  of  alumina  and 
clay  substance  is  without  foundation. 

From  the  foregoing  pages  it  will  be  readily  understood  how  feeble 
and  unsatisfactory  are  the  theories  criticised  and  that  the  investiga- 
tions hitherto  made  have  led  to  no  results  of  importance.  Hence  there 
are  reasons  for  supposing  that  an  application  of  the  H.P.  theory  of 
silicate  constitution  to  the  hardening  of  porcelain  cements  is  not  with- 
out interest. 

Before  attempting  this,  however,  it  is  desirable  to  enquire  whether 
the  porcelain  cements,  as  such,  are  single  chemical  compounds,  as  it  is 
only  then  that  they  can  be  elucidated  in  the  light  of  the  silicate 
theory. 

As  the  result  of  numerous  investigations  made  by  them  in  the 
manufacture  of  porcelain  cements  and  of  their  studies  of  such  cements 
as  are  now  obtainable  commercially,  the  authors  of  the  present  volume 
have  reached  the  conclusion  that  these  substances  are  really  single 
chemical  compounds,  chiefly  calcium  aluminosilicates. 

The  chief  reason  for  supposing  them  to  possess  this  unitary 
character  is  the  manner  in  which  they  are  produced  :  useful  cements 
can  only  be  made  from  clays  (hydro-aluminosilicates)  and  lime  or  other 
bases  mixed  in  definite  stoichiometric  proportions  and  heated  to 
redness. 

It  is  also  impossible  to  separate  a  porcelain  cement  into  different 
ingredients  by  mechanical  treatment,  such  as  washing  with  an  inert 
fluid.  Such  fractions  as  are  obtained  in  this  manner  all  have  the  same 
composition. 

The  unitary  character  of  these  compounds  is  confirmed  by  the 
following  : — It  might  be  supposed  that  the  silicate  powder  is  composed 
of  mixtures  of  calcium  aluminate  and  calcium  silicate  or  calcium 
aluminate  and  aluminosilicate,  or  of  silica,  calcium  aluminate  and 
aluminosilicate.  These  constituents  could  then  be  readily  separated 
on  account  of  their  different  specific  gravities.  But  no  such  separation 
is  possible  !  The  high  resistance  to  acids  of  such  mixtures  in  the  form 
of  half -hardened  cements,  as  found  by  Morgenstern  and  Kulka,  would 
be  inexplicable.  The  contrary  is  really  the  case  !  Furthermore,  the 
presence  of  some  constituents,  such  as  calcium  aluminate  or  calcium 
silicate,  is  thereby  excluded,  as  these  products,  even  after  being  heated 


208  CONSEQUENCES   OF  THE   H.P.    THEORY 

to  redness,  readily  absorb  C02  from  the  air.  On  mixing  a  given 
porcelain  cement  with  the  cement  acid  an  evolution  of  C02  should 
therefore  be  observable,  but  this  is  not  the  case. 

The  objection  may  be  raised  that  a  study  of  the  Patent  Specifica- 
tions leads  to  the  conclusion  that  many  porcelains  cannot  be  single 
compounds.  Thus  0.  Hoffmann  (German  patent  No.  199,664,  Kl.  30h 
of  7th  April,  1907)  claims  a  "  Method  of  producing  dental  cements 
characterised  by  the  use  of  aluminosilicates  alone  or  in  admixture 
with  other  substances." 

A  suggestion  of  the  non-unitary  character  of  porcelain  cements  is 
also  given  in  Rawitzer's  German  patent,  No.  196,510,  Kl.  30h  of  20th 
November,  1905,  in  which  he  claims  "  the  production  of  a  dental 
cement-powder  for  transparent  dental  stoppings  which  is  to  be  mixed 
with  phosphoric  acid  before  use."  This  powder  is  made  by  "  mixing 
heated  but  unfused  aluminium  silicate  A12O3  Si02  with  a  previously 
melted  mixture  of  calcium  aluminum  oxide  and  silica." 

The  study  of  commercial  porcelain  cements  made  by  the  manu- 
facturers previously  indicated  show  beyond  all  doubt  that  their 
dental  cements  were  not  made  according  to  this  recipe  !  For  instance, 
a  "  cement "  which  contained  a  large  proportion  of  precipitated 
aluminosilicate  was  entirely  useless  as  a  dental  cement  on  account 
of  the  ready  solubility  of  the  precipitated  aluminosilicate  in  acids,  and 
the  ready  decomposition  of  the  "  cement  "  by  acids.  The  ordinary 
porcelain  cement  made  by  the  same  manufacturer  is,  like  all  other 
cements  of  clay,  very  resistant  to  acids,  so  that  these  cements  cannot 
contain  a  large  proportion  of  precipitated  aluminosilicate. 

There  is  no  doubt  that  the  various  porcelain  cements  do  contain 
admixtures  of  salts  (basic  and  acid)  and,  possibly,  small  quantities  of 
precipitated  aluminosilicate,  these  being  added  to  give  certain  definite 
characteristics  to  the  material  and  to  regulate  the  time  of  setting  and 
hardening. 

It  is  also  well  known  that  only  in  the  rarest  cases  are  the  recipes 
in  the  Patent  Specifications  correct  for  making  commercial  products. 
For  instance,  the  patentee  of  the  well  known  Rostaing  cement  was  the 
first  to  use  zinc  phosphate  for  dental  purposes.  Yet  Rostaing  was, 
after  Jung's365  recommendations,  so  careful  and  took  such  pains  to 
express  himself  so  broadly  and  in  such  an  incomprehensible  manner 
that  it  has  not,  so  far,  been  found  possible  to  produce  a  cement  having 
all  the  properties  possessed  by  Rostaing's  own  preparation  by  follow- 
ing the  directions  in  the  Patent  Specification. 

Hence  the  Patent  Specifications  cannot  be  regarded  as  being 
opposed  to  the  unitary  nature  of  the  porcelain  cements. 

A  physico-chemical  Theory  of  the  Hardening  of  Porcelain  Cements 

In  formulating  a  theory  of  the  hardening  of  porcelain  cements,  the 
following  matters  must  receive  special  attention  : 

(a)  The  chemical  constitution  of  the  porcelain  cements. 


ARE   PORCELAIN   CEMENTS  MIXTURES?  209 

(6)  The  attraction  of  aluminosilicates  for  acids  and  bases.* 
'  (c)  The  physico-chemical  progress  of  the  hardening. 

(a)  The  Chemical  Constitution  of  the  Porcelain  Cements 

It  has  already  been  shown  that  a  hydro-aluminosilicate  of  the 
formula 

II 


I      I 
H20(Si-Al-Al-Si) 

contains  two  kinds  of  hydroxyls  :  a-  and  s-hydroxyls  ;  the  former 
playing  the  most  important  part  in  ultramarines  and  the  latter  in 
Portland  cements. 

In  Portland  cements  the  hydrogen  of  s-hydroxyls  —  the  s-hydrogen 

—  may  be  substituted  by  monovalent  basic  groups,  viz.  R"  •  OH, 

—  R"  •  O  •  R"  -  OH,  etc.,  where  R"=Ca.  These  are  termed  "  hydrobasic 
groups  "  and  according  to  the  number  of  R"-atoms  are  indicated  by 
(1),  (2),  etc.    By  separation  of  the  elements  of  water  in  two  neighbour- 
ing, i.e.  ortho-hydrobasic,  side-chains,  the  anhydrobasic  groups  : 

-  0  •  R"\0         -O  -  R"  •  O  -  R"\0     t 
—  O  •  R"/  —  O  •  R'  •  O  •  R"/ 

are  formed  and  are  distinguished  according  to  the  number  of 
R"-atoms  by  2°,  3°,  4°,  etc.  (p.  166). 

The  porcelain  cement  powders  differ  from  the  above  silicate 
cements  inasmuch  as  they  contain  only  a  few  silicate  side-chains  ; 
and  the  number  of  R"-atoms  is  1. 

The  following  are  typical  porcelain  cements  : 


R'O  •  6  A1O  •  6  Si0       R"0  •  6  A10  •  5  Si0        2  R'O  •  3  Al  0*  •  10  Si0 


23  •  2  •        23 


jo__/  \/    \/  \/    \  — 1° 

10=|Si|Al|Al|Si|=1o  etc. 

4R"O-6Al203-12SiO2 

These  porcelain  cements  also  differ  from  other  silicate  cements  in 
that  they  only  form  transparent,  stone-like  masses  when  mixed  with 
certain  acids,  viz.  aluminophosphoric  acids,  or  such  of  their  salts  as 
have  a  certain  composition,  to  be  mentioned  later. 

*  The  authors  of  the  present  volume  use  the  term  acido-  or  baso-phile  (from  philos 
=fond  of)  for  any  substance  which  has  an  attraction  for  an  acid  or  basic  dye-stuff. — 
A.  B.  S. 


210  CONSEQUENCES   OF- THE   H.P.   THEORY 

The  Attraction  of  the  Aluminosilicates  for  Acids  and  Bases 

The  acido-  and  baso-philism  of  the  aluminosilicates  must  be 
specially  considered,  as  this  property  of  the  aluminosilicates  plays  an 
important  part  in  the  reactions  under  consideration. 

For  example,  in  the  hydro-aluminosilicate 


I      I     il      I 
H12  (Si  •  Al  •  Al  •  SAi), 

both  the  a-  and  s-hydroxyls  are  acido-  and  baso-philic,  i.e.  the  a- 
hydrogen  and  the  s-hydrogen  may  be  substituted  by  monovalent  acid 
and  basic  radicles.  There  is  a  great  difference  between  the  degree  of 
acido-  and  baso-philism  *  of  these  hydrogen  atoms  :  the  a-hydrogen 
atoms  are  strongly  acidophilic  and  only  feebly  basophilic,  but  the 
5-hydrogen  atoms  are  strongly  basophilic  and  are  only  feebly  acido- 
philic. 

These  properties  of  hydro-aluminosilicates,  which  are  very  im- 
portant in  connection  with  the  reactions  which  occur  in  the  hardening 
of  cements,  may  be  further  shown  in  the  following : 

1 .  The  topaz  molecule 

Fl    FL  Fl 


il      I 
Fl    F12  Fl 

must,  if  the  foregoing  hypothesis  is  correct,  have  the  monovalent 
fluoric  acid  radicle  strongly  bound  to  the  aluminium  radicle  and  only 
feebly  to  the  weakly  acidophilic  silicon  radicle.  In  any  case  the 
fluorine  must  be  bound  more  strongly  to  the  aluminium  radicle  than 
to  the  silicon  radicle. 

The  fact  that  the  topazes  contain  at  least  8  fluorine  atoms,  shows 
that  when  natural  changes  occur  the  fluorine  splits  off  from  the 
silicon  ring  and  not  from  the  aluminium  one,  i.e.  the  fluorine  is  bound 
more  strongly  to  the  aluminium  than  to  the  silicon  ring,  as  the  theory 
implies. 

2.  The  relatively  feeble  basophilism  of  the  a-hydroxyls  and  the 
strong  basophilism  of  the  s-hydroxyls  are  shown  by  the  interesting 
studies  of  Gans367  on  the  "  artificial  zeolites  "  or  "  permutites."  Gans 
found  that  the  aluminosilicates  showed  a  variation  in  the  strength  of 
the  bond  between  them  and  the  alkalies  and  alkaline  earths, 
the  bases  in  some  cases  being  readily  and  completely  replaced  by 

*  See  footnote  on  p.  209. 


ACIDO-  AND  BASO-PHILISM  211 

others,  whilst  in  others,  substitution  could  only  be  effected  with 
difficulty. 

Gans  inferred  (in  agreement  with  the  theory  stated  above)  that  the 
readily  replaceable  alkalies  and  alkaline  earths  are  combined  with 
alumina,  those  bases  which  are  replaced  with  greater  difficulty  being 
attached  to  the  silicon.  In  other  words,  he  concluded  that  the  a- 
hydroxyls  are  feebly  basophilic  and  the  s-OH  groups  are  strongly 
basophilic. 

Gans  has  applied  this  ready  replaceability  of  the  a-bases  of  the 
aluminosilicates  in  an  ingenious  and  practical  manner.  For  instance, 
in  the  sodium  silicate  A,  viz.  : 

Na  Na  Na  Na 

I      I      I       I 

Na— /\/\/\/\_  Na 

**    |  Si  |  Al|  All  Si  | 
~~ 


Na  Na  Na  ISTa 
A. 

the  a-sodium  must  be  readily  replaced  on  treatment  with  aqueous 
solutions  of  Ca,  Fe",  Mn,  etc.,  forming  B,  viz.  : 

Na    R" 

I      I 

N£ 


ia 
B. 
R"=Ca,  Fe,  Mn,  etc. 

Conversely*  the  compound  A  may  readily  be  formed  by  treating  B 
with  an  aqueous  solution  of  sodium  chloride. 

The  great  technical  importance  of  such  properties  of  the  a-bases  is 
obvious.  Thus,  by  suitable  treatment  of  the  sodium  silicate  A  with 
water,  it  can  remove  calcium  and  magnesium  bases  from  solution,  i.e. 
it  can  be  made  use  of  in  softening  hard  water. 

The  a-bases  may  also  be  used  for  other  industrial  purposes,  e.g. 
to  replace  potassium  in  molasses  and  syrups  in  the  sugar  industry  by 
sodium  or  calcium. 

For  this  reason  the  following  patents  (see  Siedler368)  are  interesting  : 

(a)  An  invention  for  treating  water  for  domestic  and  technical 
purposes,  distinguished  by  filtering  the  water  through  hydrous  alumino- 
silicates,  whereby  the  undesired  bases  such  as  iron  oxide,  manganese 
oxide,  lime,  magnesia,  etc.,  are  replaced  by  others  which  are  desirable 
or  at  least  harmless. 

(b)  An  invention  for  replacing  the  potash,  in  sugar  syrups  and 
molasses,  by  other  bases,  distinguished  by  filtering  the  said  syrups  and 


CONSEQUENCES   OF  THE   H.P.   THEORY 

molasses  through  aluminosilicates,  whereby  an  exchange  of  bases 
occurs,  the  potassium  in  the  syrups  being  replaced. 

3.  The  acido-  and  baso-philism  of  the  aluminosilicates  are  also 
shown  by  their  amphichromatophilism,  i.e.  their  relation  to  both  acid 
and  basic  dye-stuffs,  as  has  been  shown  by  Hundeshagen369  in  the  case 
of  kaolin.    Concerning  this,  Hundeshagen  wrote  :    "A  peculiar  form 
of  amphichromatophilism  is  observable  in  kaolin,  which  behaves  as 
though  the  silica  and  alumina  could  act  independently  towards  dye- 
stuffs.    The  influence  of  the  silica  is  by  far  the  strongest,  and  it  is  to 
this  that  clay  owes  its  very  basophilic  character ;  almost  equal,  in  fact, 
to  that  of  amorphous  silica.    At  the  same  time  there  is  a  weaker,  yet 
still  distinct,  oxyphilism  which  is  completely  analogous  to  the  oxy- 
philism  of  free  alumina." 

Hundeshagen  therefore  considers  that  in  the  kaolin  molecule  there 
are  both  alumina-hydroxyls  (=a-hydroxyls)  and  silica-hydroxyls 
(=s-hydroxyls). 

4.  The  acido-  and  baso-philism  of  kaolin  may  also  be  observed  in 
the  colours  known  as  "kaolin-lakes,"  which  are  formed  by  the  action 
of  kaolin  on  acid  and  basic  dye-stuffs.  The  basophilism  is  stronger  than 
the  acidophilism,  so  the  kaolin  lakes  with  basic  dye-stuffs  play  a  highly 
important  part  in  technology  of  lakes,  whilst  kaolin-lakes  containing 
acid  dye-stuffs  have  a  much  feebler  colouring  power  and  are,  technically, 
of  much  less  importance. 

5.  According  to  Hundeshagen,  the  acido-  and  baso-philism  of 
kaolin  are  due  to  the  fact  that  kaolin  can  withdraw  acids  from  acid 
solutions  and  bases  from  alkaline  ones. 

6.  The  acidophilism  of  the  a-hydroxyls  of  kaolin  is  shown  by  the 
constitution  of  ultramarine,  and  particularly  from  the  behaviour 
(observed  by  Silber)  of  the  compound  : 

Na12(Si-Al-AAl-SAi) 

towards  HC1  and  that  of  the  product  thus  formed, 

Na8H4(Si-Al-Al-Si), 

towards  AgN03,  as  well  as  by  the  formation  of  the  sodalites  (p.  152). 
The  somewhat  strong  acidophilism  of  the  a-hydroxyls  and  the  very 
strong  basophilism  of  the  s-hydroxyls  are  of  importance  in  connection 
with  physio-chemical  reactions  which  take  place  during  the  hardening 
of  the  porcelain  cements,  as  described  in  the  next  section. 

(c)  The  Physio-chemical  Eeactions  occurring  during  Hardening 

The  hardening  of  porcelain  cements  is  physio-chemically  analogous 
to  that  of  other  silicate  cements,  such  as  Portland  and  slag  cements, 
the  molecules  undergoing  a  series  of  hydration  phases,  just  as  do  those 
of  Portland  cement  (p.  173).  The  porcelain  cements  are  also  "  hydrau- 
lites  "  (p.  174),  but,  unlike  the  Portland  and  slag  cements,  they  only 
harden  in  the  presence  of  certain  acids.  If  the  powdered  portion  of  a 


THE  HARDENING  OF  DENTAL  CEMENTS 


213 


porcelain  cement  is  more  basic  than  usual,  acid  salt  solutions  may 
induce  hydration  phases. 

Two   classes   of  porcelain  cements   may,   conveniently,  be  dis- 
tinguished : 

1.  Porcelain  cements  of  which  the  fluid  portion  is  acid — acid 
cements  or  ^.-cements. 

2.  Porcelain  cements  of  which  the  fluid  portion  is  an  acid  salt 
solution  * — saline  or  E-cements. 

The  2-cements  have  several  advantages  over  the  A  -cements. 
The  chemical  reactions  involved  in  hardening  porcelain  cements 
consist  chiefly  of  two  parts  : 

(a)  Hydration,  and 

(6)  Condensation,  or  formation  of  an  acid  or  salt  with  simultaneous 
loss  of  water. 


(a)  Hydration 

Hydration  consists,  as  in  the  hardening  of  Portland  cement,  in  a 
series  of  hydration  phases  as  shown  in  the  following  example  : 


10==  Si  I  All  All  Si  I     _ 


4  RO  •  6  A1203  •  12  Si02 
(a) 


I  I 

=SiAlAlSi 


I  I 

RO  •  2  H20 . 6  A1203  •  12  Si02 
(b) 


1       I 

\/ 

Si  I  Al  I  Al  I  Si 


I       I      I       I 

1o==/\/\/\/\==1o 

r  J  Si  |  Al  |  Al  |  Si]=io 

I  I  I       I      I      I 

4  RO  •  3  H20  •  6  A1203  •  12  Si02    4  RO  •  4  H20  •  6  A1203  •  12  Si02 

(c)  (d) 


4  RO  -  5  HaO  •  6  A1203  •  12  SiO, 
(e) 

*  Although  the  term  '  '  acid  salt  solutions  '  '  is  used  for  convenience,  it  should  be  under- 
stood that  acid-reacting  salts  are  really  meant,  and  not  the  true  acid  salts  which  con- 
tain H-ions.  Solutions  of  metallic  salts  are  known  (p.  228),  which  do  not  appear  to 
contain  H-ions  and  yet  have  an  acid  reaction. 

Even  if  the  acid  reaction  of  these  fluids  is  referred  to  the  presence  of  H-ions,  or 
if  these  ions  should  be  found  in  some  of  them,  there  still  remains  a  large  difference 
between  a  porcelain  cement  containing  free  acid  and  one  containing  an  acid  salt,  par- 
ticularly when  the  physiological  action  of  the  cement  is  considered. 


CONSEQUENCES  OF  THE   H.P.   THEORY 

111 

\/\/\ 

SilAllAl  Si 


I!        I        I       II 
!•—  /\/\/\/\— 

- 


1  o  _  '         I         I         I         I  _  i  o  /-\\  _  I  _  /I  \ 

II      I      I     II  II      I      I     II 

4  RO  •  6  H20  •  6  A1203  •  12  Si02    4  RO  •  10  H20  •  6  A1203  •  12  Si02 

(*)  (g) 

This  large  number  of  hydration  phases  is  accompanied  by  a  notable 
development  of  heat,  particularly  at  the  beginning. 

(b)  Condensation 

As  soon  as  the  hydration  —  assisted  by  the  acid  or  acid  salt  solution 
—  ceases,  the  second  stage  of  hardening  —  condensation  —  commences. 

If  the  fluid  portion  of  the  cement  is  a  complex  acid,  as  shown  by 
the  acidophilic  a-hydroxyls,  water  will  be  separated  and  the  acid 
radicle  will  attach  itself  to  the  silica  molecule. 

On  account  of  the  somewhat  strong  acidophilism  of  the  a-hydroxyls 
on  the  one  hand  and  the  very  strong  basophilism  of  the  s-hydroxyls 
on  the  other,  it  is  highly  probable  that  acids  will  attach  themselves 
to  the  silica  ring  without  any  separation  of  base  from  the  silica  side  of 
the  molecule. 

The  constitution  of  a  hardened  mass  of  an  -4-cement  will,  thus,  be  : 


—  m 


A    A 


According  to  this  constitution,  if,  for  instance,  A  is  an  alumino- 
phosphoric  acid,  such  a  substance  must  be  a  strongly  acid  salt  of  a 
triple  acid. 

The  addition  of  a  complex  acid  to  a  cement  powder  is  by  no  means 
a  neutralisation  of  the  former  in  the  ordinary  sense  of  this  word, 
although  on  account  of  its  insolubility  the  hardened  mass  may  react 
neutral  to  litmus.  There  is,  in  fact,  a  large  number  of  substances 
which,  being  insoluble,  react  neutral  to  litmus  and  yet  are,  constitu- 
tionally, acids.  Kaolin  is  a  typical  substance  of  this  kind. 

A  hardened  2-cement  has  probably  an  analogous  constitution  : 


aq. 


THE   HARDENING   OF  DENTAL  CEMENTS  215 

A  completely  saturated  substance  of  this  kind  is,  therefore, 
analogous  to  Thugutt's  sodalites  (p.  60)  and  the  E-ultramarines  whose 
mode  of  formation  has  been  shown  in  previous  pages  to  be  due  to  the 
formation  of  condensation  products.  The  ^4-cements,  on  the  contrary, 
are  analogous  to  the  ^4 -ultramarines  (p.  140). 

These  structural  formulae  indicate  that  a  molecule  of  a  cement  may 
be  combined  with  four  molecules  of  acid  or  of  2,  but  this  can  only 
be  the  case  occasionally. 

The  above  structural  formulae  for  fully  saturated  dental  cements 
are  only  for  a  given  case,  as  the  structure  of  these  substances  must, 
naturally,  vary  with  the  ratio  of  powder  to  fluid.  Some  of  these 
cements  may,  for  example,  have  the  formula 


(1)= 
(1)= 


OH  OH 


others  contain  an  excess  of  acid  (2)  or  of  uncombined  A  or  2.  The 
constitution  of  hardened  cements  of  other  compositions  may  be 
regarded  as  analogous. 

The  physio-chemical  reactions  occurring  during  hardening  are 
thus  clearly  shown  by  means  of  this  theory.  On  the  physical  side,  the 
following  may  be  added  : 

If  the  cement  mass  is  regarded  as  a  sphere  composed  of  different 
layers  as  in  Fig.  3,370  the  hardening  takes  place  from  the  circum- 
ference towards  the  centre.  The  outer  layer  a 
hardens  without  any  external  pressure,  but  in  the 
case  of  6,  any  expansion  is  opposed  by  the  harden- 
ing outer  layer  a.  The  same  occurs  with  layers  c  and 
d,  only  they  cannot  expand  so  much.  Hence  the 
hardness  and  density  of  the  mass  must  increase  as 
the  interior  is  approached  and  the  outermost  layer 
must  be  the  softest.  An  examination  of  phos- 
phate cements  confirms  this  view,  the  outer  portion  of  an  old  dental 
stopping  being  more  or  less  worn,  whilst  the  interior  is  found  to  be 
much  harder. 

Consequences  of  the  Theory  and  the  Facts 
A 

From  the  theory  it  follows  that  the  formulae  calculated  from  the 
analyses  of  the  porcelain  cements  must  be  arranged  to  represent 
compounds  whose  existence  is  theoretically  possible.  Unfortunately, 
very  few  analyses  of  porcelain  cements  have  been  published.  The 


216  CONSEQUENCES   OF  THE   H.P.   THEORY 

investigations  of  the  authors371  have  shown  that  the  powders  contain 
approximately 

CaO  A1203  Si02 

6-12%      38-50%     40-44% 

One  analysis  leads  to  the  formula 

ca  ca 

/\/\_l 

Al|Si)>=l0         (Ca=JCaO) 
~ 

3  CaO  •  6  A1203  •  10  Si02  •  Loss  on  ignition 
Calcd.    11.20      40.80        40.60  8.00 

Found  12.10      38.19        40.60  8.23 

The  6-12%  CaO  in  the  porcelain  cements  shows  that  the  powder 
contains  fewer  R"  side-chains  than  the  Portland  cements.  This 
relatively  small  proportion  of  CaO  also  explains  the  great  resistance  of 
these  cements  to  acids,  as  experiments  with  complex  acids  have  shown 
that  the  power  of  the  molecule  for  combining  with  a  base  increases 
inversely  as  the  amount  of  base  present  (pp.  94,  108,  262,  263,  265, 
etc.).  The  non-separation  of  this  CaO  by  the  action  of  the  fluid 
portion  of  the  cement  may  also  be  regarded  as  being  due,  in  all 
probability,  to  the  acidophilism  of  the  Al-  and  the  basophilism  of  the 
Si-rings. 

B 

The  absorption  of  water  during  hardening  must  be  capable  of  being 
represented  stoichiometrically,  as  it  is  in  Portland  cements.  The 
hardened  mass  must  contain  various  forms  of  combined  water  :  water 
as  — R"  •  OH,  water  in  the  form  of  OH-groups  attached  to  the  silicon 
ring  and  "  water  of  crystallisation."  Of  these,  the  maximum  amount  of 
water  combined  with  — R"  and  with  silicon  respectively  must 
a  priori  be  capable  of  prediction.  No  direct  determinations  of  these 
forms  of  water  have  been  published. 

C 

The  hydration  of  the  porcelain  cements  must  proceed  gradually 
like  that  of  the  Portland  cements.  It  must,  therefore,  be  possible  to 
prove  a  gradual  growth  of  the  various  OH-groups  by  determining  the 
amount  of  water  in  the  porcelain  cements  at  various  periods  during 
the  hardening. 

This  consequence  of  the  theory  was  confirmed,  in  the  case  of 
Portland  cements,  by  a  series  of  hydration  experiments  by  v.  Teicheck 
and  others  (p.  180),  but  no  such  determinations  have,  as  yet,  been 
made  with  porcelain  cements. 


THE   HARDENING   OF  DENTAL   CEMENTS  217 

D 

The  duration  of  the  various  hydration  phases  is  a  very  interesting 
subject.  In  the  case  of  the  porcelain  cement  powders,  with  their 
relatively  low  content  of  base,  the  duration  of  the  hydration  phases 
must,  cceteris  paribus,  depend  on  the  following  factors  : 

1.  The  constitution  of  the  silicate  molecule. 

2.  The  acidity  of  the  cement  acid. 

3.  The  temperature  at  which  the  hardening  occurs. 

4.  The  proportion  of  water  in  the  cement  fluid. 

5.  The  physical  conditions  of  the  cement  powder. 

As  regards  the  first  factor — the  constitution  of  the  silicate  molecule 
— it  is  clear  that  the  various  silicate  molecules  must  hydrate  at 
different  rates. 

As  an  increase  in  the  acidity  of  the  cement  fluid  must  increase  the 
speed  of  hydration,  it  is  clear  that,  cceteris  paribus ,  those  porcelain 
cements  of  which  the  fluids  contain  more  acid  must  harden  more 
rapidly  than  those  with  a  less  acid  fluid. 

As,  on  the  contrary,  the  hydration  begins  more  readily  when  the 
basic  content  of  the  silicate  molecule  is  increased,  a  reduction  of  the 
acidity  of  the  cement  fluid  must  effect  a  corresponding  increase  in 
the  basic  content  of  the  silicate  molecule  if  a  definite  rate  of  hardening 
is  to  be  reached. 

The  temperature  at  which  the  hardening  occurs  exercises  an 
important  influence  on  the  rate  of  hardening,  the  higher  the  tempera- 
ture the  quicker  the  hardening,  and  vice,  versa.  The  extent  to  which 
the  rate  of  hardening  is  increased  by  a  rise  of  (say)  10°  in  temperature 
must  be  determined  by  direct  experiment. 

For  a  definite  acidity  in  the  fluid  portion  of  the  cement,  the  rate 
of  hardening  must  naturally  depend  on  the  proportion  of  water  in 
the  fluid :  the  larger  the  proportion  of  water  the  more  rapid  the 
hardening,  and  vice  versa,  as  in  the  former  a  quicker,  and  in  the  latter 
a  slower  hydration  occurs. 

The  ability  of  the  silicate  molecule  to  undergo  hydration  also 
depends,  cceteris  paribus,  on  the  physical  condition  of  the  cement 
powder  :  the  coarser  the  powder  the  slower  and  feebler  the  hydration, 
the  finer  the  texture  the  greater  its  reactability. 

This  consequence  of  the  theory  is  fully  confirmed  by  experience. 
With  some  ^4 -cements  the  hardening  is  so  rapid  that  the  powder  must 
contain  coarse  grains  as  well  as  fine  ones  in  order  to  reduce  the  rate  of 
hardening  within  convenient  limits,  or  special  instructions  must  be 
issued  to  users  that  the  fluid  must  be  added  in  small  quantities  and 
very  slowly. 

There  is  a  possibility,  in  the  case  of  some  of  the  slower  2-cements, 
of  so  regulating  the  rate  of  hardening  that  at  blood  heat  (37°  C.)  they 
harden  at  a  normal  rate  and  can  thus  be  used  for  dental  purposes.  This 
is  effected  by  arranging  the  size  of  the  grains  in  the  powder  and  the 
concentration  of  the  fluid  portion  of  the  cement. 


218  CONSEQUENCES   OF  THE   H.P.   THEORY 

At  the  ordinary  temperature,  the  2-cements  usually  harden  more 
slowly  than  the  JL-cements,  and  a  number  of  writers  have  considered 
this  to  be  a  defect  in  the  E-cements.  As  a  result  of  this  slower  harden- 
ing of  the  E-cements  they  contain  uncombined  2  (i.e.  uncombined, 
feebly  acid  salts)  in  solution  for  a  longer  time  after  the  commencement 
of  the  hardening  than  do  the  ^t-cements,  and,  consequently,  they  have 
an  acid-like  reaction  towards  litmus  for  a  longer  period.  This  has  led 
to  the  false  conclusion  that  the  2-cements  are  detrimental  to  the 
pulpa. 

In  reaching  this  conclusion  the  following  have  been  overlooked  : 

1.  That  the  dental  cements  should  not  harden  at  the  ordinary 
temperature,  but  at  blood  heat,  and  this  is,  as  already  shown,  the 
temperature  at  which  they  harden  best. 

2.  No  importance  can  be  attached  to  the  suggestion  that  these 
cements  are  harmful  to  the  pulpa,  as  the  reddening  of  litmus  by  them 
is  not  due  to  a  strong  A  -acid,  but  to  a  weakly  2-acid  salt  solution. 

E 

It  also  follows  from  the  theory,  that  the  hardening  of  a  porcelain 
cement  must  occur  in  a  series  of  phases.  This  consequence  of  the 
theory  is  fully  confirmed  by  practical  experience.  Morgenstern372  has 
shown  that,  in  most  cements,  the  first  hardening  is  followed  by  molecu- 
lar changes,  which  in  some  cases  are  completed  within  3  hours,  but  in 
others  are  not  fully  completed  in  24  hours.  In  confirmation  of  this  is 
the  fact,  proved  by  Morgenstern,  that  the  strength  of  these  cements 
increases  if,  after  the  first  period  of  3  to  24  hours,  they  are  kept  out  of 
contact  with  air  or  moisture. 

Wege373  has  also  distinguished  two  stages  in  the  hardening  of 
porcelain  cements. 

1.  The  setting  stage,  which,  according  to  Wege,  "lasts  15  to  20 
minutes.     If  it  takes  place  at  blood  heat,  it  is  accompanied  by  a 
marked  evolution  of  heat  owing  to  the  rapidity  with  which  the  physio- 
chemical  changes  occur.    During  this  stage  these  cements  become  so 
hard  that  they  may  be  cut  and  polished.  At  ordinary  room  temperature 
the  hardening  takes  place  much  more  slowly. 

"  The  sensitiveness  of  the  freshly  mixed  cement  to  moisture  and 
to  saliva  is  characteristic  of  the  first  stage  of  the  hardening  of  a 
porcelain  cement.  It  is,  therefore,  necessary  to  perform  the  operation 
of  tooth-stopping  in  such  a  manner  that  all  saliva  is  excluded  until  the 
cement  is  hardened." 

2.  The  stone-forming  stage  commences  "  after  15  to  30  minutes  (at 
blood  heat).    The  chemico-physical  reactions  which  occur  during  this 
second  stage  of  the  hardening  are  less  energetic  than  those  in  the  first 
stage,  and  the  heat  evolved  is  so  small  as  to  be  scarcely  measurable." 

11  The  mass  in  the  second  stage  is  less  sensitive  to  moisture  and 
saliva.  This  sensitiveness — which  shows  itself  by  '  killing  '  any  cement 


TOXIC   ACTION   OF  J-CEMENTS  219 

mass  mixed  with  saliva — diminishes  more  and  more  until  it  eventually 
ceases  completely. 

"  The  c  stone-forming  '  process  may  be  completed  in  a  few  hours 
or  it  may  take  2  to  3  days,  different  cements  varying  considerably.  It  is 
during  this  second  stage  that  the  cement  attains  its  maximum  hardness 
and  density." 

Schreiber374,  in  his  critical  studies,  has  also  repeatedly  called 
attention  to  the  various  phases  of  hardening  of  the  porcelain  cements. 

The  inference  from  the  theory  that  the  hardening  of  the  porcelain 
cements  occurs  in  a  series  of  phases  is  thus  in  agreement  with  the  facts. 

It  is  clear  that,  previous  to  the  "  stone-forming  "  stage,  the 
hardening  of  the  porcelain  cements  may  be  hindered  by  the  action  of 
water,  alkalies,  and  diluted  acids,  and  it  is  a  serious  error,  in  studying 
the  resistance  of  these  cements  to  acids  and  alkalies,  to  treat  them  with 
these  reagents  before  the  stone-forming  stage  of  the  hardening  is  com- 
pleted. As  already  mentioned,  Morgenstern  and  Schreiber  have 
clearly  shown  the  nature  of  this  error  in  a  series  of  experimental  studies 
made  by  them. 

F 

In  the  light  of  the  H.P.  theory,  the  fact  that  porcelain  cement  masses 
have  a  higher  resistance  to  dilute  acids  than  is  possessed  by  ivory  or 
the  enamel  of  natural  teeth  is  explicable.  The  acid  in  the  fluid  portion 
of  the  cement  does  not  decompose  the  silicate  molecule  ;  it  does  not 
cause  the  separation  of  any  bases  which  can  form  easily  soluble  salts 
with  phosphoric  acid  or  aluminophosphoric  acid.  The  acid  in  these 
cements  only  assists  the  hydration  of  the  silicate  molecule  and  adds 
itself  to  the  latter.  Dilute  acid,  if  it  does  not  act  on  the  hardened 
molecule,  may,  if  it  has  as  great  an  affinity  for  the  silicate  molecule  as 
the  cement  acid,  effect  a  further  hydration  and  may  replace  it,  though 
this  is  seldom  the  case,  with  dilute  lactic  and  acetic  acids. 

This  indicates  that  the  cement  mass  is  not  readily  attacked  by 
acids,  a  fact  which  has  been  proved  experimentally. 

The  Toxic  Action  of  the  ^-cements  in  the  Light  of  the  New  Theory 

From  what  has  been  written  in  the  foregoing  pages,  the  constitu- 
tion and  properties  of  the  porcelain  cements  must,  undoubtedly,  be 
regarded  as  new  members  of  the  great  class  of  silicate  compounds.  It 
is  therefore  desirable,  in  the  light  of  the  H.P.  theory,  to  find  an  answer 
to  a  question  which  is  both  theoretically  and  practically  of  the  greatest 
importance.  It  has  been  stated  that  some  porcelain  cements  have  a 
serious  disadvantage  in  that  they  cause  dangerous  inflammation  and 
destroy  the  nerves  (pulpa)  of  the  teeth,  with  all  the  consequences  which 
follow  these  actions. 

For  several  years  there  has  been  a  bitter  fight  as  to  whether  the 
toxic  character  of  these  silicates  may  be  prevented.  The  chief  difficulty 
in  solving  this  problem  appears  to  lie  in  the  lack  of  knowledge  of  their 


CONSEQUENCES   OF  THE   H.P.   THEORY 

constitution  and  the  course  of  the  reactions  during  the  hardening  of 
the  material.  Moreover,  the  question  as  to  the  toxic  action  of  porce- 
lain cements  containing  strong  acids — the  A  -cements  are  the  only 
ones  which  have  been  found  to  affect  the  pulpa — is  purely  a  physio- 
logico-chemical  one,  and  yet  no  one  has  endeavoured  to  answer  it 
with  the  assistance  of  physiological  chemists  and  their  discoveries  of 
toxines,  although  this  would  seem  to  be  a  conditio  sine  qua  non  to  any 
satisfactory  solution. 

The  following  lines  contain  the  results  of  an  effort  to  ascertain  the 
cause  of  the  harmful  action  of  some  cements  and  to  find  a  means  of 
preventing  it.  This  effort  is  based  on  a  consideration  of  the  constitu- 
tion and  the  reactions  occurring  in  the  hardening  of  ^.-cements  and  on 
a  study, of  the  manner  in  which  the  toxines  have  been  found  to  react 
physiologically. 

In  studying  the  causes  of  the  toxic  action  of  the  A  -cements  the 
following  consequences  of  the  theory  are  important : 

1.  The  action  of  the  acids  in  the  fluid  portion  of  the  A  -cements — 
the  aluminophosphoric  acids — results,  primarily,  in  the  hydration  of 
the  silicate  molecule,  i.e.  in  the  formation  of  a-,  s-  and  basic-hydroxyls. 
The  combination  of  the  acid  with  the  molecule  is  a  secondary  result, 
and  is  due  to  the  acidophilic  OH-groups. 

The  cement,  prepared  by  mixing  the  powder  and  the  fluid  together 
into  a  plastic  mass,  is  at  once  forced  into  the  dental  cavity  under  con- 
siderable pressure.  It  is,  therefore,  clear  that  it  must  contain  a 
considerable  amount  of  free  aluminophosphoric  acid  which  may 
gradually  find  its  way  to  the  pulpa. 

2.  According  to  the  theory,  which  is  based  on  the  fact  of  the  strong 
basophilism  of  the  silicate  ring  and  the  weak  acidophilism  of  the 
alumina  ring,  it  follows  that,  in  all  probability,  the  free  alumino- 
phosphoric acid  will  not  cause  the  separation  of  the  least  particle  of  base. 
This  highly  probable  consequence  of  the  theory  becomes  a  certainty 
when  the  repeatedly  observed  high  resistance  to  acids  of  the  un- 
combined  or  incompletely  combined  A  -cements  is  taken  into  considera- 
tion. 

This  consequence  of  the  theory,  which  is  in  complete  agreement 
with  the  observed  properties  of  the  cement  masses,  is  of  great  import- 
ance in  studying  the  causes  of  the  toxic  action  of  the  ,4-cements. 
Thus,  it  might  be  assumed  that  the  6-12%  lime  in  the  A  -cement 
powders  would  be  separated  on  mixing  the  powder  with  the  acid  fluid, 
and  that  if  the  lime  present  reached  a  definite  proportion  it  might,  in 
this  way,  completely  prevent  the  toxic  action  of  the  acid  owing  to  the 
combination  of  the  acid  and  lime.  From  both  the  theory  and  the 
observed  behaviour  of  the  ^4-cements  towards  acids  it  follows  that  no 
such  separation  of  the  base  can  occur. 

The  improbability  of  any  separation  of  lime  being  brought  about 
by  the  aluminophosphoric  acid  on  simply  mixing  the  silicate  powder 
and  the  acid  fluid  together,  is  confirmed  by  the  behaviour  of  highly 


TOXIC   ACTION   OF   ^-CEMENTS 

basic  cements  which  have  been  hardened  by  treatment  with  acid,  such 
as  the  zinc  phosphate  cements,  the  powdered  portion  of  which  contains 
90%  of  zinc  oxide. 

In  commerce,  as  may  readily  be  seen  from  a  study  of  the  literature 
of  the  subject,  there  are  two  kinds  of  zinc  phosphate  cements  : 

(a)  Those  in  which  the  fluid  portion  contains  a  strong,  free  acid  ; 
and 

(6)  Those  in  which  the  fluid  portion  contains  a  considerable  amount 
of  a  stronger  base,  e.g.  zinc  oxide. 

The  difference  is  shown  in  the  following  Table,  due  to  H.  Paschkis  : 

Composition  of  Zinc  Cements 


Name 

"  Fluid  Portion  " 

Contains 

Poulson 

fluid 

no  zinc 

Entrop 
Ash 

» 

„     ,, 

Griinbaum 

little  zinc 

Poulson 
Rostaing 

crystalline 
fluid 

much  zinc 
»         » 

It  is  clear  that  these  two  kinds  of  zinc  phosphate  cement  may  have 
different  chemico-physiological  properties.  In  this  connection  it  is 
interesting  to  notice  that  one  of  the  most  famous  workers — Miller, 
Professor  of  Dentistry  at  Berlin  University376 — comments  on  the 
repeatedly  observed  destruction  of  pulpse  by  zinc  phosphate  cements 
(p.  232),  whilst  another  equally  famous  operator — Prof .  Black377 — has 
observed  no  such  destruction  by  zinc  phosphate  cements.  These 
contradictory  opinions  can  only  be  explained  by  assuming  that 
Miller  used  cements  containing  free  acid,  whilst  Black  used  those  in 
which  the  fluid  portion  contained  salts.  Other  operators  have  also 
reported  contradictory  results,  some  recommending  the  use  of  a 
protective  medium  below  the  cement  stopping  and  others  advising  the 
direct  use  of  zinc  phosphate  cement  as  providing  the  most  suitable 
protection  for  the  pulpa.378 

The  destructive  action,  on  the  nerves,  of  zinc  phosphate  cements 
containing  strong  acids  in  a  free  state  in  the  fluid  portion  can  only  be 
explained  by  supposing  that  not  merely  the  6-12%  of  base  in  porcelain 
cements,  but  even  the  90%  of  base  in  the  zinc  cement  powder,  cannot 
prevent  the  destructive  action  of  the  free  acid  on  the  nerves  at  the 
moment  when  the  mass  is  introduced  into  the  cavity  in  the  tooth. 

This  surprising  fact  admits  of  a  complete  explanation  :  the  harden- 
ing of  a  cement  is  essentially  a  slow  physio-chemical  process  and  it 
cannot,  by  the  time  the  mass  is  introduced  into  the  cavity,  have 
proceeded  far  enough  for  the  neutralisation  of  the  strong  acid  to  effect 
the  separation  of  the  base.  This  behaviour  of  the  highly  basic  zinc 


222  CONSEQUENCES  OF  THE  H.P.   THEORY 

phosphate  cements  thus  affords  a  further  confirmation  of  the  im- 
probability of  any  separation  of  the  base  by  the  action  of  the  cement 
acids  on  silicate  powders  so  poor  in  basic  material  as  are  the  A  -cements 
at  the  moment  of  their  introduction  into  the  dental  cavity. 

3.  In  the  light  of  the  H.P.  theory,  the  fully  hardened  A  -cements  are 
really  "  sodalites  "  (p.  214).  The  acid  is  added  to  the  silicate  molecule 
because  of  the  acidophilism  of  the  a-hydroxyls.  Experience  has  shown 
that  this  acidophilism  of  the  silicate  molecule  is  never  strong,  and  in 
the  case  of  acid  dye-stuffs  the  "  lakes  "  produced  are,  technically,  of 
minor  importance. 

There  is  a  danger  on  account  of  the  low  acidophilism  of  the  a- 
hydroxyls,  that  after  a  long  time  a  separation  of  free  acid  may  occur 
and  the  pulpa  be  destroyed,  the  A  -cements  thus  resembling  a  sleeping 
volcano  which  may  start  its  destructive  action  at  any  moment. 

According  to  the  new  theory,  the  completion  of  the  hardening  of 
the  A  -cements  need  not  prevent  the  acid  in  them  from  acting  detri- 
mentally. Definite  reports  made  by  various  practical  dentists  show 
that  the  deleterious  action  has  been  observed  a  long  time  after  the 
"  stopping  "  had  been  inserted  ;  in  some  instances  after  an  interval 
of  a  whole  year.  In  one  case,  disease  of  the  pulpa,  resulting  in  the 
death  of  the  patient,  set  in  more  than  a  year  after  a  shallow  cavity  had 
been  stopped  with  ^4-cement. 

The  toxic  action  of  the  A  -cements  has  now  been  shown  to  be  due  to 
that  of  the  free  aluminophosphoric  acid  present.  The  question  arises 
as  to  whether  this  toxic  action  can  be  proved  by  chemico-physio- 
logical  experiments  in  which  these  free  acids  are  compared  with  other 
toxic  substances.  The  answer  to  this  question  forms  the  subject  of  the 
following  section : 

The  Causes  of  the  Neurotropism  of  Aluminophosphoric  Acids 
(Ehrlich's  Theory) 

The  term  "  neurotropism  "  was  suggested  by  Ehrlich379  to  in- 
dicate the  poisonous  action  of  any  material  on  nerve-substance. 

Before  it  can  be  stated  that  a  given  substance  is,  theoretically,  a 
neurotrope  it  is  necessary  to  understand  why  modern  physiological 
chemists  consider  that  neurotropism  is  the  result  of  chemical  action. 
The  famous  physiologist  and  bacteriologist,  P.  Ehrlich,  was  the  first  to 
suggest  that  only  those  chemical  substances  are  neurotropic  which 
form  a  definite  chemical  compound  with  the  nerve-fibres380  (side-chain 
theory).  Erhlich  reached  this  conclusion  as  a  result  of  his  study  of 
the  so-called  vital  colour  processes.  Ehrlich  has  shown  that  the  various 
dye-stuffs  become  localised  in  the  organism  according  to  their  chemical 
constitution.  For  instance,  methylene  blue  has  a  special  attraction 
for  living  nerve-fibres ;  other  dye-stuffs  are  chiefly  retained  by  the  fatty 
organs  and  still  others  by  the  substance  forming  the  kidneys. 

As  the  theory  of  the  chemical  combination  of  the  toxines  is  of 
fundamental  importance  if  a  satisfactory  theory  which  will  explain  the 


THE    CAUSES   OF  NEUROTROPISM  223 

observed  properties  of  porcelain  cements  is  to  be  obtained,  it  is  neces- 
sary to  mention  briefly  those  facts  having  any  bearing  on  the 
theory  which  have  been  observed  by  all  well-known  physiological 
chemists. 

Ehrlich's  theory  is  confirmed  by  the  following  facts  : 

1.  Analysis  of  cases  of  poisoning  by  toxines.    It  is  well  known,  for 
instance,  that  when  toxines  are  introduced  directly  into  the  blood- 
stream they  rapidly  disappear.381    The  rapid  combination  of  injected 
toxines  with  the  blood  has  also  been  observed  by  von  Behring382, 
A.  Knorr383,  Bomstein384,  de  Croly385  and  others. 

2.  The  investigations  of  von  Behring386  on  tetanus  afford  a  special 
confirmation  of  the  theory  of  the  chemical  combination  of  the  toxines. 
If  animals  which  are  peculiarly  liable  to  tetanus  are  inoculated  with 
tetanus  poison,  this  is  found  in  all  the  organs  except  the  central 
nervous  system.    In  other  words,  the  poison  is  only  feebly  combined 
in  the  organs  first  mentioned,  but  it  enters  into  definite  chemical 
combination  with  the  nerve-substance  and  cannot  then  be  detected. 

The  following  fact  also  supports  Erhlich's  theory  :  Knorr  has 
drawn  up  a  '*  Scale  of  Sensitiveness  to  Tetanus,"  and  finds  that  the 
poisonous  dose  for  a  hen  is  200,000  times  that  for  a  horse,  the  amount 
being  calculated  in  grammes  of  poison  per  gramme  of  animal  weight. 
Hens  have  been  found  by  Kitasato  to  be  practically  immune  from 
tetanus. 

The  very  slight  sensitiveness  of  hens  as  compared  with  horses  may 
be  explained  by  Ehrlich's  theory  as  due  to  lack  of  combining  power. 
This  is  confirmed  by  the  experiments  of  Metschnikoff387,  Azakawa388, 
and  of  Fermi  and  Pernossi389,  which  show  that  insensitiveness  to 
certain  poisons  is  accompanied  by  the  easy  recognisability  of  the 
toxine  in  the  organism  for  a  long  time  after  its  introduction. 

4.  The  well-known  experiment  of  Robert  Koch390  is  a  particularly 
valuable  confirmation  of  the  theory  of  the  chemical  combination  of  the 
toxines.     Koch  wished  to  sterilise  infected  animals  with  corrosive 
sublimate,  but  found  that  the  largest  practicable  doses  had  no  influence 
on  the  parasites,  the  animals  being  killed  more  easily  than  the  para- 
sites.   This  can  be  readily  understood  in  the  light  of  Ehrlich's  theory  ; 
the  sublimate  is  organotropic,  but  not  parasitotropic,  i.e.  it  forms 
definite  chemical  compounds  with  the  substances  forming  the  important 
organs  of  the  infected  animals,  but  has  no  chemical  action  on  the  cells 
of  the  parasites. 

5.  Low's  experiments  on  the  action  of  oxalic  acid  on  plants,  is 
another  interesting  and  valuable  confirmation  of  Ehrlich's  theory. 

Oxalic  acid  is  well  known  as  a  powerful  poison  to  both  animals 
and  plants,  and  its  action  was  found  by  Low  to  be  due  to  its  forming 
definite  compounds  with  lime  salts.  Hence,  according  to  Low,  oxalic 
acid  is  only  poisonous  to  those  plants  whose  cells  contain  lime  salts, 
and  it  can  have  no  poisonous  action  on  plants,  the  cells  of  which  are 
free  from  calcium  compounds.  Low  has  fully  proved  by  direct  experi- 


224  CONSEQUENCES   OF  THE   H.P.   THEORY 

ments  that  plants  which  contain  no  lime  salts  are  not  poisoned  by 
oxalic  acids. 

Further  important  confirmation  may  be  found  in  the  results  of  a 
large  number  of  experiments,  all  of  which  are  fully  indicative  of  the 
production  of  definite  chemical  compounds.391 

Amongst  others,  Pasteur's  Immunisation  Therapy,  Behring's 
Serum  Therapy  (Diphtheria  serum),  Chemicotherapy,  the  work  of  Koch 
and  Uhlenhut  on  the  use  of  atoxyl  in  the  cure  of  malaria,  and  the 
chemical  treatment  of  infectious  diseases  (syphilis)  by  Ehrlich  and 
Hata  all  yield  therapeutic  results  in  support  of  Ehrlich's  side-chain 
theory. 

There  can,  therefore,  be  no  doubt  that  the  theory  of  the  chemical 
combination  of  the  toxines  is  fully  established. 

If  it  is  desired  to  explain  the  neurotropism  of  the  ^1-cements  (i.e. 
the  poisonous  action  of  the  aluminophosphoric  acids  on  nerve-sub- 
stance) it  must  be  clearly  shown  that  these  substances  form  definite 
chemical  compounds  with  the  nerve-fibres. 

In  order  to  do  this  it  is  clearly  necessary  to  : 

1.  Have  a  clear  idea  of  the  chemical  constitution  of  the  nerve- 
fibres,  and 

2.  Produce  facts  which  show  the  existence  of  a  chemical  relation- 
ship between  the  aluminophosphoric  acids  and  the  nerve-fibres. 

I.   The  Chemical  Constitution  of  the  Nerve-fibres 

The  nerve-fibres,  like  all  other  animal  fibres  such  as  wool  and  silk, 
belong  to  the  proteins,392  i.e.  to  those  substances  whose  constitutions 
have  been  so  admirably  studied  by  Emil  Fischer  and  his  students.  These 
investigators393  claim  that  it  has  been  positively  proved  that  the 
proteins  contain  amino-acids,  the  same  fundamental  substances 
appearing  in  the  most  widely  differing  proteins,  but  in  very  varying 
proportions,  so  that  one  or  other  amino-acid  may  be  entirely 
wanting.  This  constitution  of  the  proteins  is  reminiscent  of  the 
aluminosilicates  which  also  contain  a  few  fundamental  substances 
combined  in  the  most  varied  proportions.  For  instance,  in  the  pro- 
teins, the  following  amino-acids  are  found  :  glycoeol,  d-alanine, 
Z-leucine,  d-glutaminic  acid,  amino-oxysuccinic  acid,  diaminoacetic 
acid,  etc. 

As  the  complete  hydrolysis  of  proteins  by  acids  and  alkalies 
always  yields  the  same  results,  E.  Fischer  and  his  associates  concluded 
that  the  amino-acids  in  them  are  not  secondary,  but  are  an  integral 
part  of  the  protein  molecules.  Hence  the  proteins  are  complex  acids 
and  must  behave  towards  acids  and  bases  in  a  manner  analogous  to 
other  complex  acids.  As  a  matter  of  fact,  the  albumens  are  usually 
represented  as  multiple  acid  bases  and  multiple  basic  acids,  i.e.  they 
have  a  marked  baso-  and  acido-philism  and  form  compounds  with  both 
acids  and  bases.  This  ability  of  the  albumens  to  combine  with  acids 
and  bases  has  been  investigated  by  several  methods.394 


THE    CAUSES   OF   NEUROTROPISM  225 

II.   The  Chemical  Relationship  between  the  Nerve-fibres  and  the 
Aluminophosphoric  Acids 

If  it  may  be  accepted  as  a  definite  fact  that  the  nerve-fibres,  like 
animal  fibres  generally,  are  chiefly  proteins  (amino-acids),  it  is  clear 
that  such  substances  may  form  definite  compounds  with  either  simple 
or  complex  acids,  especially  as  Friedheim  and  his  associates  have 
found,  as  the  result  of  a  large  number  of  experiments,  that  complex 
acids  can  not  only  combine  with  bases,  but  also  with  other  acids,  and 
other  chemists  have  proved  the  existence  of  amino  groups. 

That  the  facts  fully  confirm  the  possibility  suggested  by  theory 
is  shown  by  the  mordanting  of  animal  fibres  by  sesquioxide  compounds 
such  as  aluminosulphates  (alums),  aluminoacetates,  etc.,  i.e.  by  the 
various  complex  alumino-acids.395  The  properties  of  the  alumino- 
phosphates — such  as  the  existence  of  aluminophosphates  with  very 
different  proportions  of  phosphoric  acid  and  alumina,  which  can  pass 
into  one  another  ;  the  impossibility  of  replacing  the  alumina  by  other 
bases  by  double  decomposition  ;  the  masking  of  the  phosphoric  acid 
by  alumina  in  agriculture,  etc. — show  that  their  constitution  is 
analogous  to  that  of  the  aluminophosphates  and  aluminoacetates,  and 
there  can  be  no  doubt  that  they  have  a  special  chemical  relationship 
to  the  nerve-fibres.  In  short,  the  aluminophosphoric  acids  are,  in 
accordance  with  Ehrlich's  theory,  neurotropes  or  nerve  poisons. 

It  is  very  probable  that  the  proteins,  like  the  aluminosilicates, 
have  a  cyclic  constitution,  i.e.  they  apparently  consist  of  N-  and  C- 
hexites  and  pentites.  The  combination  of  animal  (nerve)  fibres  and 
the  complex  alumino-acids — the  corrosives — is  most  probably  analo- 
gous to  that  of  the  complex  acids  :  two  neighbouring  OH-groups  in 
the  animal  fibre  combining  with  two  similar  (ortho)  OH-groups  in  the 
alumino-acid  with  loss  of  water.  The  resultant  complex  can  then,  in 
an  analogous  manner  (i.e.  on  losing  water),  unite  with  dye-stuffs,  the 
combination  of  these  being  thus  effected  by  means  of  the  OH-groups 
in  the  alumino-acids.  From  this  it  follows  that  only  dye-stuffs  with 
ortho-hydroxyl  groups  can  combine  with  alumino-acids  and  can  be 
used  as  dyes.  This  interesting  consequence  of  the  theory  has  been 
fully  confirmed  by  the  experiments  of  C.  Liebermann  and  St.  Kon- 
stanecki396,  who  have  shown  that  the  only  oxyanthracinones  which  are 
fixed  dyes  are  those  containing  two  ortho-hydroxyl  groups.  C. 
Liebermann  has  converted  non-dyeing  colours  into  strong  dyes  by  the 
introduction  of  two  ortho-hydroxyl  groups,  particularly  in  the  case  of 
fluorescines,  eosines,397  malachite  green,398  fluorines,399  oxyaurenes,400 
etc. 

What  can  be  said  in  regard  to  the  physiologico-chemical  action  of 
the  2-cements  ? 

The  experience  of  Black  and  Schreiber  with  S-phosphate  cements 
shows  that  the  2-silica  cements  are  non-poisonous  to  the  nerves  of  the 
teeth.  The  plastic  mass  of  Z-cement  does  not  contain  free  alumino 


226  CONSEQUENCES  OF  THE   H.P.   THEORY 

phosphoric  acid,  but  an  acid  saturated  with  zinc  oxide,  i.e.  a  zinc  salt, 
which  must,  naturally,  behave  in  a  different  physiologico-chemical 
manner  towards  the  nerves.  According  to  Ehrlich's  theory,  all  toxic 
action  is  excluded  in  the  case  of  2-cements,  as  investigations  on  the 
dyeing  of  animal  fibres  show401  that,  in  the  absence  of  mordants,  the 
colour  can  only  be  fixed  on  wool  and  silk  when  the  dye-bath  is  acid, 
i.e.  only  when  the  dyestuff-acid  is  in  a  free  state.  From  this  it  follows 
that  only  free  acids  have  any  action  on  the  nerve-fibres,  salts  being 
inert  in  this  respect ;  in  other  words,  solutions  of  zinc  salts  can  form 
no  definite  chemical  compound  with  nerve-fibres,  i.e.  they  are  not 
neurotropic. 

It  is  very  remarkable  that,  according  to  Siem's  investigations,738 
complex  compounds  of  aluminium  (sodium  alumino-lactate),  when 
injected  subcutaneously  into  animals,  are  found  to  be  highly  poisonous. 
On  injecting  relatively  large  doses  of  these  compounds  into  the  blood, 
death  occurred  after  seven  to  ten  days.  The  daily  subcutaneous  in- 
jection of  small  quantities  into  dogs,  cats  and  rabbits,  caused  death 
within  three  to  four  weeks  after  the  introduction  of  a  total  weight  of 
0.25  to  0.30  grammes  A1203  per  kilog.  of  animal  weight. 

The  fact  discovered  by  Dollken739  in  repeating  Siem's  experiments 
is  even  more  interesting.  Dollken  confirmed  Siem's  conclusions  and 
also  found  that,  in  accordance  with  the  H.P.  theory,  these  poisonous 
aluminium  compounds  are  essentially  nerve  poisons.  He  found  that  in 
animals  which  had  died  from  injections  of  these  substances  the  nerve- 
roots  were  degenerated  and  that  marked  changes  had  occurred  in  the 
nerve-cells.  The  central  nervous  system  is  the  part  most  affected  by 
these  poisonous  aluminium  compounds  ;  the  outlying  nerves  not  being 
appreciably  affected. 

Siem  and  Dollken  have  also  shown  that  it  is  a  further  characteristic 
of  aluminium  poisoning  that  time  is  required  before  any  symptoms  of 
poisoning  are  observable.  Neither  investigator  noticed  any  acute 
symptoms  of  poisoning,  even  when  large  doses  were  administered. 
This  experience  is  a  complete  agreement  with  the  symptoms  accom- 
panying poisoning  by  silicate  cements  of  the  "  A  "  type,  in  which,  as 
previously  stated,  the  action  of  poison  does  not  make  itself  observable 
until  after  weeks,  months,  or,  in  some  cases,  more  than  a  year. 

The  objection  may  be  raised  that,  according  to  the  H.P.  theory, 
neutral  salts  of  complex  alumino-acids  and  particularly  sodium 
alumino-lactate,  should  be  wcw-poisonous,  as  the  harmlessness  of  the 
zinc  aluminophosphates  (i.e.  of  the  2-cements)  was  thus  explained. 
This  objection  is  not  well  taken,  as  it  is  necessary  to  remember  that 
some  salts,  like  the  sodium  compounds  of  complex  acids,  readily 
dissociate  and  their  anions  can  then  enter  into  reaction.  For  this  reason 
the  feebly  dissociable  zinc  salt  possesses  advantages  over  the  free 
acids.  Moreover,  it  is  especially  important  to  observe  that  Siem  used 
extremely  dilute  solutions,  whilst  the  fluid  portion  of  the  2-cements  is 
highly  viscous  and  is  thus  different  from  the  ^4-cements.  The  prob- 


THE  ACID   REACTION   OF   Z-CEMENTS  227 

ability  of  extensive  dissociation  or  decomposition  of  the  fluid  portion 
of  the  2-cements  in  hollow  teeth  is  very  remote. 

It  should  also  be  noted  that,  apart  from  any  particular  theory,  there 
can  be  no  doubt  that  free  acids  can  combine  with  nerve-substance  far 
more  readily  than  can  salts,  and  from  this  point  of  view  the  Z-cements 
must  be  more  advantageous  than  the  A  -cements  for  physiologico- 
chemical  purposes. 

The  objection  may  be  raised  that  the  fluid  portion  of  the  2-por- 
celain  cements  is  very  concentrated,  and  that  the  acid  reaction  is 
due  to  a  hydrolysis  of  the  salt,  i.e.  that  these  salts  must  contain  free 
aluminophosphoric  acid,  even  if  only  in  small  quantity.  This  objection 
is  quite  erroneous,  as  the  acid  reaction  of  metallic  salts  is  not  neces- 
sarily a  sign  of  hydrolysis,  because  many  metallic  salts  (including 
nickel  sulphate,  manganese  chloride  and  copper  sulphate)  which,  hi 
aqueous  solution,  react  strongly  acid  may  be  shown,  on  physio- 
chemical  grounds,  to  be  quite  free  from  hydrolysis. 

As  the  question  whether  the  acid  reaction  of  an  aqueous  solution 
is  a  definite  sign  of  the  presence  of  free  acid  has  not  been  clearly 
answered,  an  attempt  is  made,  in  the  folio  whig  lines,  to  deal  with  it  in 
accordance  with  the  experimental  material  available. 


Does  the  Acid  Reaction  of  an  Aqueous  Solution  of  an  Acid  Salt  always 
indicate  Hydrolysis  and  the  Presence  of  Free  Acid  ? 

The  non-hydrolysis  of  a  number  of  acid-reacting  solutions  of 
metallic  salts  may  be  shown  : 

(a)  By  determining  their  coefficient  of  conductivity,  and 

(b)  By  spectrum  analysis  of  the  solution. 


(a)  Conductivity  Determinations 

The  following  simple  means  of  determining  whether  a  salt  is  hydro- 
lysed  in  aqueous  solution  is  due  to  Ostwald.  If  the  molecular  con- 
ductivity of  a  solution  of  one  gramme-molecule  of  a  salt  in  1024  litres 
of  water  at  25°  C.  is  represented  by  yui024  and  the  conductivity  of  the 
same  weight  of  the  salt  in  32  litres  of  water  at  the  same  temperature 
is  represented  by  ^82,  from  the  difference  A  between  these  two  numbers 
it  can  at  once  be  seen  whether  the  substance  is  hydrolysed  or  not.  If, 
for  instance,  the  difference  A  is  approximately  20,  no  hydrolysis  has 
occurred,  but  if  A  is  considerably  above  20,  a  hydrolysed  salt  is 
present.402 

A  number  of  salts,  such  as  nickel  sulphate,  cobalt  chloride,  man- 
ganese chloride,  copper  chloride  and  copper  nitrate,  when  in  aqueous 
solutions  react  like  acids,  yet  the  value  of  A  shows  that  according  to 
Ostwald 's  rule  they  are  not  hydrolysed,  as  may  be  seen  from  the 
following  Table,403  in  which  no  number  is  significantly  above  20. 


228  CONSEQUENCES  OF  THE   H.P.  THEORY 

Conductivity  Difference 

Salt  A 

Nickel  sulphate 18.6 

Manganese  chloride 18.5 

Cobalt  chloride 18.2 

Copper  chloride 20.5 

Copper  nitrate         18.6 

Copper  sulphate  also  has  an  acid  reaction,  yet  the  determination 
of  the  conductivity  of  a  number  of  aqueous  solutions  of  copper  sulphate 
show,  according  to  Ostwald404,  that  this  substance  is  not  hydrolysed. 
Ostwald  has  shown  that  the  conductivity  increases  steadily  with  the 
dilution  of  the  solution,  and  from  this  and  from  the  conductivity  of  an 
infinitely  dilute  solution  he  concludes  that  solutions  of  copper  sulphate 
contain  Cu-  and  S04-  ions,  but  no  H-  ions. 

(b)  Spectrum  Analysis 

According  to  Knoblauch405  and  Nernst406,  spectrum  analysis  affords 
a  very  delicate  method  for  showing  the  constancy,  or  otherwise,  of  the 
constitution  of  a  substance.  If  the  absorption  spectrum  of  a  solution 
of  the  substance  changes  with  the  concentration  a  change  must  have 
occurred  in  the  constitution  of  the  substance.  According  to  Nernst407, 
innumerable  tests  have  shown  that  a  very  small  change  in  the  consti- 
tution is  readily  shown  by  the  difference  in  the  absorption  spectrum. 

If  acid-reacting  solutions  of  metallic  salts,  such  as  copper  sulphate, 
underwent  the  slightest  hydrolysis  this  could  be  detected  by  the  change 
in  the  absorption  spectrum,  so  that  by  examining  the  spectrum  of 
solutions  of  different  strengths  it  is  possible  to  ascertain  whether  the 
slightest  hydrolysis  has  taken  place. 

Acid-reacting  copper  sulphate  which,  according  to  its  conductivity, 
is  not  hydrolysed  in  aqueous  solution,  has  also  been  spectroscopically 
examined  by  several  investigators,  including  P.  Glan408,  H.  W.  Vogel409, 
and  Knoblauch410.  Glan  and  Vogel  found  that  the  solid  and  dissolved 
substances  both  have  the  same  absorption  spectrum,  so  that  no  change 
in  its  constitution  and  therefore  no  hydrolysis  occurs  when  acid- 
reacting  copper  sulphate  is  dissolved  in  water. 

Knoblauch  dissolved  half  a  gramme-molecule  of  copper  sulphate  in 
0.37  litres  of  water  and  an  equal  quantity  in  325  litres  of  water  ;  the 
character  of  the  spectrum  of  both  these  solutions  was  identical  and 
Knoblauch  therefore  concluded  that  in  neither  case  did  water  effect 
any  hydrolysis  of  the  salt. 

In  these  ways,  the  best  methods  of  physical  chemistry  have  shown 
that  a  number  of  acid-reacting  metallic  salts  are  not  hydrolysed  when 
in  aqueous  solution,  i.e.  they  do  not  contain  any  free  acid. 

The  objection  may  be  raised  that  (a)  Carrara  and  Vespignani  in 
measuring  the  rate  of  saponification  of  methyl  acetate  at  25°  C.  by 


THE   ACID   REACTION   OF   Z-CEMENTS  229 

means  of  copper  sulphate,  and  (b)  Davis  and  Fowler  by  inverting  sugar 
with  copper  sulphate  solution,411  have  shown  quantitatively  that  the 
hydrolysis  of  the  copper  sulphate  does  occur  and  that  the  investiga- 
tions of  these  scientists,  at  first  sight,  appear  to  show  a  slight  though 
definite  hydrolysis.  These  experiments  must,  nevertheless,  be  re- 
garded as  useless,  as  Donnan412,  who  first  introduced  them,  found  that 
they  were  by  no  means  free  from  objection  inasmuch  as  they  contradict 
the  results  of  conductivity  determinations.  They  are  specially 
erroneous  as  their  authors  worked  on  the  false  assumption  that  the 
saponification  or  inversion  was  effected  exclusively  by  hydrogen-ions. 
If  this  assumption  were  correct  it  must  follow  that  : 

1.  The  inversion  of  the  sugar  must  increase  with  the  dilution  of 
the  acid,  as  the  number  of  the  H-ions  increases  as  the  solution  becomes 
more  dilute.     Precisely  the  opposite  is  the  case :  the  inversion  pro- 
ceeding more  rapidly  with  the  stronger  acid.413 

2.  The  rate  of  inversion  must  be  reduced  by  adding  neutral  salts 
of  the  acid  used,  as  this  would  reduce  the  number  of  H-ions.     Yet 
according  to  Nernst  the  opposite  is  the  case :   the  presence  of  an 
equivalent   amount   of   potassium  salt  of   the  given  acid  increasing 
the  rate  of  inversion  by  about  10  per  cent. 

3.  Salts  which  react  acid  to  indicators  must  also  invert  sugar,  as 
they  should  (on  the  assumption  named)  contain  H-ions.  Yet  H.  Ley414 
has  observed  that  many  salts  which  react  acid  to  indicators  behave 
like  neutral  salts  as  regards  sugar. 

4.  Salts  which  contain  no  H-ions  should  never  invert  sugar,  yet 
H.  Ley  and  others415  have  found  that  many  so-called  neutral  salts, 
e.g.  chlorides  of  strong  bases,  invert  sugar  to  a  small  yet  measurable 
extent .    The  contradiction  between  practice  and  the  theory  that  H-ions 
are  necessary  for  the  inversion  of  sugar  was  explained  long  ago, 
Arrhenius416  having  shown  that  other  ions  greatly  increase  the  action 
of  the  H-ions.    If,  however,  the  inversion  of  sugar  may  be  effected  or 
increased  by  other  ions  it  is  clearly  useless  to  employ  this  method  to 
ascertain  what  hydrolysis  (if  any)  has  taken  place  in  a  given  solution. 
The  above-mentioned  facts  are  also  opposed  to  the  assumption  that 
sugar  inversion  can  only  occur  in  the  presence  of  H-ions,  as  Ley  and 
others  have  effected  it  in  complete  absence  of  these  ions.    If,  on  the 
other  hand,  it  is  agreed  that  anions  may  influence  the  inversion,  it  is 
impossible  to  understand  why  the  inversion  cannot  be  due  to  the  S0'4- 
ion  in  the  copper  sulphate,  as  two  absolutely  unexceptionable  methods 
—electrical  conductivity  and  spectrum  analysis — have  shown  the  non- 
hydrolysis  of  the  solution. 

There  can  be  no  doubt  that  there  are  some  metallic  salts  which 
react  like  acids  and  yet  do  not  contain  a  trace  of  free  acid.  Hence 
the  acid  reaction  of  the  Z-cement  fluids  cannot  be  used  as  an  argument 
for  the  presence  in  them  of  free  acid  ;  in  other  words,  the  acid  reaction 
of  the  Z-cement  fluids  does  not  in  any  way  imply  the  possibility  of  a 
chemical  combination  of  the  cement  fluid  and  the  nerve-fibres. 


230  CONSEQUENCES  OF  THE   H.P.   THEORY 

The  physiologico-chemical  properties  of  the  A-  and  2-cements 
fully  agree  with  the  properties  which  have  been  observed  in  practice. 

Practical  Experiences  with  A-  and  --cements  in  regard  to  their 
Physiologico-chemical  Behaviour 

The  numerous  experiments  already  referred  to  leave  but  little 
doubt  that  the  -4-cements  are  nerve-poisons  and  that  the  Z-cements 
are  harmless. 

In  the  year  1904  or  1905,  shortly  after  the  silicate  cements  had 
been  placed  on  the  market,  several  attempts  were  made  to  prevent  the 
poisonous  action  of  the  A  -cements.  For  this  purpose  Selowsky417, 
Hentze418,  Sachs419,  Bruck420,  Detzner421,  Scheuer422,  Escher423  and 
others  recommended  that  : 

1.  A  very  thick  cement  mixture  should  be  used  so  that  any  excess 
of  poisonous  acid  in  the  fluid  would  eventually  combine  with  the 
excess  of  powder. 

2.  Before  inserting  the  cement,   a  neutral  material  should  be 
introduced  into  the  dental  cavity,  so  as  to  prevent  the  acid  from 
reaching  the  pulpa. 

In  spite  of  the  most  careful  use  of  these  protective  materials, 
dental  literature  contains  many  reports  of  destroyed  pulpse  and  of 
some  deaths  due  to  the  acid.  Thus,  in  1906  the  following  (German) 
dentists  reported  cases  of  poisoning  and  the  uselessness  of  a  stiff  paste 
and  of  protecting  pieces  :  Heinsheimer424,  Silbermann425,  Reissner426, 
and  in  1908,  Schreiber427.  In  1909  Baldus428  confirmed  this  view.  Of 
the  many  (German)  dentists  who  in  1909  reported  deaths  due  to 
pulpa  poisoning  caused  by  A  -cements,  only  the  following  need  be 
mentioned  :  C.  Wolff,  Aachen429,  Marx430,  Horstmann431,  Schulte432, 
Gerhardt,  Leipzig433,  Wild434,  Albrecht435,  Peckert436,  Stein-Mann- 
heim437, Gunzert438  and  Port439. 

Of  these,  Wild  alone  found  30  deaths  due  to  ^4-cements.  Still  more 
recently,  Feiler440  has  reported  that  in  spite  of  the  greatest  care,  11 
cases  of  poisoning  occurred,  and  enquired  whether  it  was  right  to  use 
silicate  cements  of  so  dangerous  a  nature  to  patients.  "  I  must  say 
that  to  me  each  case  is  a  peculiarly  unpleasant  memory,  so  that  I  am 
constantly  asking  myself  whether  we  are  justified  in  using  a  material 
which,  in  spite  of  the  greatest  care  and  skill,  places  the  patient  in  so 
much  danger." 

Feiler  has  also  reported  a  fatal  case  following  the  use  of  an  A- 
cement  as  follows  :  "  The  following  incident,  told  to  me  by  Privy 
Councillor  Partsch,  is  worth  careful  consideration.  I  take  the  following 
from  the  official  medical  report :  '  On  the  16th  December,  1906,  a  year 
after  the  stopping  of  a  superficial  cavity  in  the  right  upper  incisor  with 
original  Ascher's  silicate  cement,  R.  G.  (22  years  of  age)  began  to  suffer 
indefinable  pains  in  the  right  side  of  his  face,  and  several  days  later  a 
pronounced  swelling  of  the  right  cheek  and  of  the  upper  and  lower 


PHYSIOLOGICAL  BEHAVIOUR  OF  PORCELAIN  CEMENTS  231 

eyelids  was  observed  ;  fever  also  commenced.  On  the  20th  December 
an  elastic  swelling,  very  sensitive  to  the  touch,  was  easily  observable  ; 
the  teeth  were  very  painful  when  pressed,  and  a  similar  swelling  near  the 
fossa  cannia  was  seen.  The  temperature  rose  to  40°  C.  with  the  pulse 
at  120.  General  condition  much  disturbed  ;  no  mental  symptoms. 
The  dentist  trepanned  two,  whereupon  pus  discharged  from  the  pulum 
cavum,  the  swelling  increased  around  the  roots  of  the  teeth  and  con- 
tained an  evil-smelling  pus.  In  the  evening  the  temperature  was  still 
38.5°C.;  the  pain  somewhat  reduced.  Next  day,  a  general  improvement. 
On  the  23rd  and  24th  no  pain  experienced  ;  patient  taken  in  closed 
carriage  to  the  dentist  for  further  treatment.  On  the  25th  he  made 
a  long  journey  unknown  to  the  doctor.  On  the  26th  headache  re- 
commenced and  on  the  27th  the  doctor  was  sent  for  and  found  con- 
siderable feverishness  and  headache,  but  no  trouble  with  the  mouth, 
apart  from  three  vomitings.  The  doctor  diagnosed  influenza,  but  the 
symptoms  increased  daily,  the  lid  of  the  right  eye  swelled,  the  eye- 
ball was  protruded  ;  general  mental  symptoms  observable  ;  the  pulse 
sank  to  56  and  became  irregular,  the  knee  reflexion  was  unsatisfactory, 
and  considerable  deep  hyperaesthesia  of  the  legs  was  found. 

"  On  the  4th  of  January  an  operation  showed  that  the  processes  had 
extended  through  the  fissura  orbitalis  inferior  to  the  eye-socket,  and 
notwithstanding  a  wider  opening  it  was  impossible  to  prevent  the 
spread  of  the  processes.  The  temperature  fell  for  a  short  time,  but  on 
the  7th  of  January  it  rose  to  40.4°  C.,  with  feverish  shivering,  and 
remained  fairly  constant  with  increasing  brain  disturbance  until  the 
exitus  letalis  on  the  18th  of  January." 

Schreiber441  in  1910,  after  reporting  a  whole  series  of  fresh  deaths 
from  diseased  pulpse  due  to  the  use  of  A  -cements,  wrote  in  strong  terms 
condemning  the  impracticability  of  the  preventive  methods  recom- 
mended. 

Freund442,  of  Breslau,  encouraged  the  use  of  ^4-cements,  and 
attributed  the  toxic  action  of  some  specimens  to  the  presence  of 
arsenic  and  not  to  the  free  acid.  A  year  later  (in  1909),443  after  some 
unfortunate  experiences  with  -4-cements,  he  openly  joined  those  who 
accept  the  acid  theory  and  discussed  the  question  as  to  who  were 
responsible  for  these {C  accidents  " — the  manufacturers  who  guaranteed 
their  products  to  be  harmless,  or  the  dentist. 

Lartschneider444  distinguishes  between  an  irritation  of  the  pulpa 
and  destroying  it.  Under  the  term  "  pulpa  irritation  "  he  groups  all 
the  cases  in  which  pain  is  felt  soon  after  the  insertion  of  the  cement. 
In  most  cases  the  pain  soon  ceased,  but  in  some  instances  it  continued 
for  several  hours.  He  has  observed  these  symptoms  in  6  to  8  per  cent. 
of  his  patients.  They  were  often  quite  independent  of  the  depth  of  the 
cavity,  and  many  of  the  worst  cases  were  those  where  no  trouble  was 
anticipated.  He  noticed  that  young,  delicate,  anaemic  patients 
suffered  most,  and  considered  that  the  fatal  cases  might  be  due  to 
anaemia. 


232  CONSEQUENCES   OF  THE   H.P.   THEORY 

Robert  Richter445  also  attributes  the  harm  done  by  these  cements 
to  the  presence  of  arsenic,  and  points  out  the  seriously  poisonous 
nature  of  this  material.  He  goes  so  far  as  to  suggest  that  the  A- 
cements  should  always  be  labelled  as  "  poison." 

Schreiber446  also  regarded  the  A  -cements  as  poisonous,  and  urged 
that  they  should  be  scheduled  accordingly.  He  also  suggested  that  in 
the  case  of  an  "  accident  "  the  dentist  should  be  held  to  be  legally 
responsible. 

It  is  interesting  to  observe  that  most  investigators  consider  that  the 
poisonous  action  is  due  to  the  free  acid. 

A.  Masur447  reports  observations  made  by  the  Breslau  dentists  on 
the  destruction  of  the  pulpa  a  short  time  after  the  use  of  A  -cements, 
the  patients  suffering  from  acute  periodontitis.  Masur  also  considers 
that  the  cause  of  the  symptoms  observed  is  to  be  found  in  the  cement 
acid.  Reissner448  also  attributes  the  periostitis  observed  by  him  to 
the  action  of  free  acid. 

Silbermann449  definitely  assumes  that  the  detrimental  action  of  the 
^4-cements  on  the  pulpa  is  due  to  the  acid  they  contain,  and  has 
endeavoured  to  prove  this  assumption  experimentally.  Later,  he 
considered  that  the  arsenic  in  the  cements  was  the  cause  of  their  toxic 
action,  but  "  the  difference  observed  in  the  pulpa  after  the  application 
of  arsenic  and  of  an  Ascher's  stopping,  which  had  resulted  in  peri- 
odontitis," led  him  to  conclude  that  the  damage  was  done  by  the  acid 
in  the  cement  and  not  by  the  arsenic.  Moreover,  arsenic-free  A- 
cements  have  the  same  toxic  action  as  others  ;  hence  it  is  not  generally 
agreed  that  the  acid  is  the  poisonous  ingredient. 

Kulka450  has  pointed  out  that,  according  to  Miller451,  the  destruc- 
tion of  the  pulpa  (p.  221)  is  by  no  means  unusual  with  zinc  phosphate 
cements,  and  is  apparently  due  to  the  phosphoric  acid  in  the  cement 
fluid.  Kulka  accepts  this  suggestion  and  also  the  similar  one  made  by 
Ottolenguis453 ;  he  also  considers  it  possible  that  the  free  acid  removes 
lime  from  the  tooth-ivory  and  affects  the  pulpa  by  partial  destruction  of 
the  dentine. 

Feiler454  does  not  accept  this  view,  as  he  found  that  on  drilling 
through  the  stopping  the  dentine  above  the  pulpa  was  unaffected,  and 
that  no  lime  had  been  removed  from  it ;  he  does,  however,  agree  that 
the  detrimental  action  of  the  A  -cements  is  due  to  the  free  acid  present, 
and  refers  to  Pawel's455  work  in  support  of  this.  Pawel  found,  by 
actual  experiments  on  animals,  that  the  acid  in  these  cements  can 
penetrate  thick  layers  of  dentine  and  can  then  damage  the  pulpa. 
According  to  Feiler,  the  chemical  irritation  of  the  excess  of  acid 
affects  the  vitality  of  the  pulpa  through  pores  or  channels  in  the  dentine 
and  destroys  its  power  of  resistance  to  bacteria.  The  latter  are  thus 
able  to  pass  through  the  channels  in  the  dentine  and  to  enter  the  blood- 
stream, thus  bringing  about  violent  processes,  the  intensity  of  which 
depends  on  the  virulence  or  pathogenity  of  the  germs  present. 

The  destruction  of  the  pulpa  which  results  from  the  use  of  porcelain 


PHYSIOLOGICAL  BEHAVIOUR  OF  PORCELAIN  CEMENTS 

cements  containing  free  acids  is  attributed  to  the  strong  acids  in  the 
cement  fluid  by  the  following  (additional)  authorities :  Biel456, 
Hentze457,  Sachs458,  Bruck459,  Apfelstadt460,  Schreiber461,  Wege462, 
Schachtel463,  etc. 

Lartschneider464  has  expressed  a  doubt  as  to  the  action  of  free 
acid  in  A  -cements  on  the  pulpa.  He  placed  small  pellets  of  cotton- 
wool saturated  with  the  fluid  portion  of  these  cements  (i.e.  with 
cement-acid)  in  the  cavities  in  infected  teeth  and  closed  the  cavity 
with  a  Fletcher's  cap.  In  some  instances  temporary  pain  was  ex- 
perienced by  the  patient,  but  it  ceased  after  a  few  hours.  In  no  case 
did  he  find  any  appreciable  destruction  of  the  pulpa  or  any  periostitic 
symptoms,  even  though  some  of  these  "  acid  fillings  "  were  retained 
in  the  teeth  for  nine  weeks. 

This  investigation  is  of  value,  but  it  does  not  invalidate  the  "  acid 
theory  "  for  the  following  reasons  : 

1.  Symptoms  are,  in  many  cases,  only  observed  after  a  very  long 
time,  sometimes  as  much  as  a  year  or  more  after  the  introduction  of 
the  stopping,  and  the  observations  made  by  Lartschneider  were  made 
in  too  short  a  time  for  the  action  of  the  acid  to  become  noticeable.    In 
this  connection  the  experience  of  another  dentist — Albrecht465 — is 
interesting.  Albrecht  was  one  of  the  first  to  use  A  -cements  extensively, 
and  he  could  not  understand  why  so  many  of  his  colleagues  complained 
of  their  deleterious  action.    More  recently,  however,  he  has  realised 
that  several  "  accidents  "  are  due  to  old  cases,  the  damage  to  the 
pulpa  taking  some  months  before  it  became  noticeable.    Two  cases  in 
particular,  in  which  he  filled  quite  shallow  cavities  with  A  -cements, 
resulted  in  the  destruction  of  the  pulpa  and  in  periodontitis  after  more 
than  a  year,  have  made  him  pessimistic  with  regard  to  these  cements. 

The  eventual  destruction  of  the  pulpa  in  the  cases  quoted  by 
Lartschneider  is,  therefore,  by  no  means  excluded. 

2.  The  plastic  silicate  mass  is  pressed  into  the  dental  cavity  under 
considerable  pressure,  whereby  the  free  acid  may  the  more  readily 
penetrate  the  pores  or  channels  in  the  dentine  and  so  reach  the  pulpa. 
If  a  pellet  of  cotton- wool  saturated  with  acid  is  used,  there  is  little 
or  no  pressure  exerted,  and  the  acid  cannot  so  readily  reach  the  pulpa  : 
it  may,  in  fact,  combine  with  the  Fletcher  cement. 

3.  It  is  not  impossible  that  only  certain  people  are  sensitive  to 
the  action  of  the  aluminophosphoric  acids,  and  that  in  his  experi- 
ments Lartschneider  had  patients   who  were  not  likely  to  develop 
pulpitis. 

If  the  harmlessness  of  the  aluminophosphoric  acids  is  assumed, 
to  what  is  the  destruction  of  the  pulpa  due  ?  Moreover,  Pawel  has 
shown  the  harmful  action  of  strong  acids  on  the  pulpa  by  direct 
experiments  on  animals  as  previously  noted  (p.  232). 

The  most  direct  proof  that  the  toxic  action  of  the  A  -cements  is 
solely  due  to  the  free  acid  they  contain  is  found  in  the  2  -cements, 
which  only  differ  from  the  former  in  the  substitution  of  a  salt  for  the 


234  CONSEQUENCES  OF  THE   H.P.  THEORY 

free  acid,  yet  are  found  in  practice  as  well  as  in  theory  to  be  perfectly 
harmless. 

No  sooner  had  the  poisonous  nature  of  the  A  -cements  been  realised 
than  an  urgent  demand  was  made  for  their  improvement  in  such  a 
manner  that  they  should  lose  their  toxic  action  completely.  Thus 
Heinsheimer466  has  stated  that  "  Beautiful  and  valuable  though  the 
Ascher  cements  are,  they  have  one  property  which  is  absolutely  neces- 
sary to  remove,  viz.  the  toxic  action  on  the  pulpa.  Otherwise,  these 
almost  ideal  materials  must  be  discarded.  These  views  are  held  by  a 
number  of  my  colleagues,  and  I  may  frankly  say  that  this  serious  dis- 
advantage is  not  due  to  the  use  of  too  soft  a  mixture  or  to  badly 
prepared  material." 

Greve  expresses  himself  to  the  same  effect :  "  Some  of  the  new 
silicate  cements  produce  excellent  results  under  suitable  conditions, 
but  an  improvement  is  essential.  If  this  cannot  be  effected  they  will 
never  attain  the  popularity  which  has  been  prophesied." 

The  warnings  of  Heinsheimer,  Greve  and  others  are  all  the  more 
significant  when  it  is  remembered  that,  according  to  Pfaff467,  diseases 
of  the  pulpa  are  the  cause  of  other  diseases  of  important  organs — 
particularly  of  the  eyes  and  ears.  Thus,  deposits  of  decomposed  matter 
on  the  pulpa,  diseases  of  the  pulpa  itself  and  of  the  membranes  sur- 
rounding the  fangs,  frequently  cause  neuralgia  of  the  trigeminus,  or 
neuritis  ascending  to  the  ganglion  gasseri  (Karewski).  The  clinical 
observation  that  the  eyes  are  affected  in  many  diseases  of  the  teeth 
has  been  made  by  numerous  ophthalmologists.  Acute  pulpit  is,  peri- 
ostitis and  empyemia  of  the  antrum  highmori  are  stated  to  be  the  causes 
of  many  eye  complaints  by  Alexander,  Keyser,  Wacher,  Lardin, 
Birch-Hirschfeld  and  others.  Pagenstecher  and  Vossius  have  also 
reported  numerous  cases.  Amongst  other  diseases  of  the  eyes  which 
have  their  origin  in  defective  teeth  are  changes  in  the  optic  nerves  and 
in  the  retina  ;  inflammation  of  the  cornea  and  of  the  conjunctiva,  or 
of  the  whole  eye-ball ;  diminished  sensitiveness  in  the  apparatus  for 
accommodation  and  in  the  iris,  affections  of  the  muscles  which  move 
the  eye-ball  and  eyelids,  diseases  of  the  tear-glands  and  ducts.  These 
have  been  observed  by  Decaisne,  Blank,  Schmidt,  Schulek,  Wedl  and 
others.  The  manner  in  which  these  diseases  are  brought  about  must 
be  sought  in  the  nerves  and  in  the  mucous  lining  of  the  mouth  ;  the 
latter  extends  to  the  jaw  from  the  ostium  pharyngeum  tubce.  to  the  drum 
of  the  ear,  so  that  inflammatory  processes  in  the  mouth  may  also 
extend  their  action  for  a  considerable  distance.  Otitis  media  and  the 
related  ascending  neuralgia  may  also  be  due  to  diseases  of  the  teeth, 
according  to  Boke,  Ziem  and  Winkler. 

Greve468,  in  1906,  attributed  the  poisonous  nature  of  the  A  -cements 
to  their  irrational  composition.  He  considered  that  the  composition  of 
the  silicate  powder  does  not  permit  it  to  neutralise  the  cement  acid, 
and  he  attributed  the  dangerous  irritation  of  the  pulpa  to  an  excess  of 
free  acid.  It  has  been  shown  that  in  the  highly  basic  zinc  phosphate 


RELATIVE  DIFFUSIBILITY  OF  A-  AND  2-CEMENTS    235 

cements  (p.  221)  the  use  of  less  acid  will  not  avoid  the  danger,  because 
no  separation  of  the  base  has  occurred  by  the  time  the  plastic  mass  is 
placed  in  the  cavity.  Nevertheless,  Greve's  work  is  important  because 
he  showed  the  value  of  bases  for  reducing  the  poisonous  nature  of  A- 
cements.  The  right  way  to  destroy  the  poisonous  nature  of  the  silicate 
cements  is  shown,  both  by  theory  and  practical  experience,  to  consist 
in  saturating  the  cement  acid  with  a  strong  basis  before  the  fluid 
portion  of  the  cement  is  mixed  with  the  powder  ;  in  other  words,  by  the 
conversion  of  -4-cements  into  2-cements. 

W.  and  D.  Asch469,  in  1908,  published  the  results  of  some  experi- 
ments with  a  transparent  2-cement,  i.e.  with  a  silicate  cement  in  which 
the  fluid  portion  consists  of  an  acid-reacting  salt  solution.  Use  of  this 
cement  in  practical  dentistry  appears  to  be  highly  satisfactory  :  the 
mass  proved,  in  accordance  with  theory,  to  be  perfectly  harmless  to 
the  pulpa.  The  practical  experiences  of  Oppler470,  Wege471,  Schach- 
tel472,  Schreiber473,  Baldus474,  etc.,  with  this  cement  have  further 
confirmed  its  absolute  harmlessness. 

Baldus  has  used  this  cement  for  more  than  a  year,  Wege  and 
Schreiber  for  several  years.  Schachtel  has  laid  this  cement  on  almost 
translucent  pulpae,  which  were  very  painful  at  the  time  of  the  opera- 
tion, but  after  a  long  time  no  harmful  symptoms  could  be  observed. 
Oppler  has  brought  this  cement  into  direct  contact  with  the  free  pulpa, 
yet  though  the  patients  were  under  observation  for  a  long  time,  he 
observed  no  irritating  symptoms,  a  result  which,  according  to  Schreiber, 
is  incredible  if  A  -cements  are  used. 

Hence,  practical  experience  is  in  full  accord  with  theory  in  regard 
to  the  absolute  harmlessness  of  the  2-cements,  just  as  both  are  agreed 
as  to  the  essential  poisonous  nature  of  the  A  -cements. 

The  2-cements  have,  in  their  physiologico-chemical  relations,  other 
advantages  over  the  ^4-cements.  It  is  open  to  argument  whether  an 
excess  of  cement  fluid  diffuses  more  rapidly  through  the  dental  capil- 
laries and  into  the  pulpa  more  rapidly  when  it  is  in  the  form  of  a 
solution  of  a  salt  or  an  acid.  The  facts  established  by  Graham740 
afford  valuable  evidence  in  this  connection.  According  to  Graham,  the 
acids  and  acid  salts  diffuse  more  rapidly  from  a  mixture  of  basic, 
neutral  and  acid  fluids  than  do  the  basic  and  neutral  ones.  The  fluid 
portions  of  the  A  -cements — which  are  usually  free,  or  practically  free 
aluminophosphoricjacids — diffuse,  cceteris  paribus,  more  rapidly  than  the 
2-cements,  as  the  latter  are  usually  saturated  with  bases.  Should  an 
excess  of  the  fluid  portion  of  the  S-cements  eventually  diffuse  towards 
the  pulpa,  it  is  by  no  means  improbable  that  during  this  time  it  would 
come  into  contact  with  cement  powder  and  so  would  become  fully 
neutralised.  In  this  way  the  slow  diffusibility  of  fluid  portions  of  the 
2-cements  is  a  great  advantage,  for  physiologico-chemical  purposes, 
over  the  more  readily  diffusible  portion  of  the  A  -cements. 

When  it  is  remembered  that  in  the  commercial  2-cements  the  fluid 
is  highly  viscous,  whilst  in  the  ^4-cements  the  fluid  is  very  mobile,  it  is 


236  CONSEQUENCES  OF  THE   H.P.   THEORY 

clear  that,  cceteris  paribus,  the  Z-cement  fluid  must  diffuse  more  slowly 
than  that  of  the  A  -cements,  and  therefore  the  former  cements  are 
preferable  to  the  latter. 

XV 
A  New  Theory  of  Glasses,  Glazes,*  and  Porcelains 

A  definite  part  of  the  silicates  known  as  glasses,  glazes  and  porce- 
lains are,  without  doubt,  definite  chemical  compounds  in  the  structure 
of  which  hexites  and  pentites  play  an  important  part. 

Some  of  the  "  glasses  "  are  compounds  of  simple  acids,  others, 
like  most  glazes  and  the  porcelains,  are,  in  so  far  as  they  are  single 
chemical  compounds,  complex  acids  or  the  corresponding  salts. 
Dumas475  considered  that  glass  has  as  definite  a  composition  as 
certain  minerals  or  that  it  is  a  mixture  of  certain  silicates  ;  the  glasses 
he  examined  corresponded  to  the  formula  Na20  •  CaO  •  4SiO2,  but, 
as  Berthier476  has  shown,  a  higher  silica  content  in  the  glass  makes  it 
harder  and  less  fusible,  whilst  lime  increases  its  resistance  to  chemical 
influences  ;  Benrath477  regards  as  "  glasses  "  those  silicates  which 
correspond  to  the  general  formula  RO  •  2  Si02.  It  is  important  to 
observe  that  it  was  Benrath  who  showed  that  the  most  suitable 
composition  for  all  useful  glasses  (excluding  optical  ones)  lies  within 
the  limits  of  Na20  •  CaO  •  6  Si02  and  5  Na20  •  7  CaO  •  36  Si02,  in 
which  Na  may  be  replaced  by  K  and  Ca  by  Pb.  The  occurrence  of  the 
figure  6  and  its  multiples  is  highly  significant. 

Zulkowski741  has  studied  the  relationship  between  the  chemical 
composition  and  the  physical  properties  of  glass,  and,  for  certain 
specimens  prepared  by  him,  he  suggests  the  following  empirical 
formula  : 

M'20  •  M"0  •  6  Si02, 

and  the  following  structural  formula  : 

/0-SiO-SiO-O-SiO-OM' 

MX 

X0  •  SiO  •  SiO  •  O  •  SiO  •  OM' 

In  this  manner  Zulkowski  regards  glasses  as  definite  chemical 
compounds.  At  the  same  time,  he  regards  the  refining  stage  in  the 
manufacture  of  glass  as  a  chemical  process  and  not,  as  is  customary, 
as  a  purely  physical  one  in  which  the  dross  particles  are  separated  on 
account  of  their  higher  specific  gravity. 

That  the  6  SiO  2  in  the  above  formula  plays  an  important  part  in 
glasses  is  recognised  by  Zulkowski,  and  based  on  the  investigations 
of  Schwarz,  which  showed  that  the  resistance  of  glasses  to  the  action 

*  Glazes  are  carefully  prepared  mixtures  of  minerals  which  are  applied  to  articles 
in  order  to  impart  a  glossy  surface  or  glaze,  the  covering  material  being  melted  into  a 
kind  of  glass  by  heating  the  article  in  a  kiln  or  suitable  oven.  Opaque  glazes  are  termed 
enamels,  but  both  words  are  used  somewhat  loosely. 


THE   CONSTITUTION   OF  GLASSES,  ETC.  237 

of  10  per  cent,  hydrochloric  acid  reaches  a  satisfactory  value  with 
glasses  of  the  character  examined  by  Zulkowski.  The  investigations  of 
Stas  and  others  have  also  shown  that  glasses  only  become  resistant  to 
the  action  of  water  when  their  composition  is  in  accordance  with  the 
above  formula. 

It  is  also  of  interest  to  observe  that  Zulkowski  has  studied  glasses 
with  5  Si02  in  the  molecule — to  which  he  attributes  an  analogous 
formula. 

In  reality,  it  is  not  the  number  6,  but  a  multiple  of  this  number 
which  is  essential,  and  glasses  containing  36SiO2  are  particularly 
important.  Thus,  the  normal  composition  of  glass  is  stated  by 
Fischer742  to  be  : 

5  Na20  •  7  CaO  •  36  Si02, 

5  K20  •  7  CaO  •  36  SiO,, 

5  K20  •  7  PbO  •  36  Si02. 

Normal  glasses  of  the  following  formulae  have  also  been  reported  : 743 

6  K20  •  2  PbO  •  2  ZnO  •  2  BaO  •  36  Si02, 
3  Na20  •  3  K20  •  3  PbO  •  3  CaO  •  36  Si02, 
3  Na20  •  3  K20  •  6  PbO  •  36  Si02. 

It  cannot  be  said  that  the  three  latter  formulae  represent  the  mini- 
mum molecular  weights,  as  formulae  can  be  constructed  from  the  same 
data  with  less  than  36  Si02.  Yet  if  the  above  formulae  are  regarded 
as  representing  the  minimum  molecular  weights,  then  glasses  must 
clearly  have  at  least  36  molecules  of  Si02  in  each  glass  molecule. 

There  are  many  people  who  believe  that  glasses  are  not  single 
chemical  compounds,  but  mixtures  or  solid  solutions.  Zulkowski  holds 
the  opposite  view,  and  has  drawn  attention  to  the  experiments  of 
Mylius  and  Foerster744,  which  show  that  glasses  are  not  mixtures,  but 
true  chemical  compounds.  Zulkowski  regards  glasses  as  acid  di- 
silicates,  because  he  is  not  in  a  position  to  give  a  formula  similar  to 
those  suggested  by  the  H.P.  theory. 

Of  special  interest  is  the  composition  of  alabaster-glass,  which, 
according  to  Zulkowski,  is  not  a  double  silicate,  but  a  pure  potassium 
meta-silicate  which  belongs  to  the  siliceous  glasses.  The  composition 
of  this  glass  he  represents  by  K20,  8  Si02.  It  is  highly  probable  that 
this  glass  has  a  molecular  weight  at  least  four  times  as  large  as  corre- 
sponds to  the  above,  i.e.  that  the  true  formula  contains  32  SiO2. 

In  addition  to  those  glasses  which  may,  possibly,  be  regarded 
as  simple  silicates,  there  are  the  glazes  and  porcelains  which  may  be 
regarded  as  fused  aluminosilicates  or  salts  of  other  complex  silicates, 
such  as  salts  of  borosilicic  acid.  Zulkowski  also  considers  that  "  on 
fusing  4  SiO  2,  2  B2O3  with  one  molecule  of  CaC03  and  one  molecule 
of  soda,  the  product  is  not  a  glassy  mixture,  but  a  homogeneous 
glass."  He  attributes  to  the  material  obtained  in  this  manner  a 
structural  formula  analogous  to  that  which  he  assigns  to  normal  glass. 

Assuming  that  the  minimum  weight  of  the  chemical  compounds 


238  CONSEQUENCES   OF  THE   H.P.   THEORY 

known  as  "  glass  "  corresponds  to  a  formula  with  36  Si02  and  that  this 
substance  is  an  acid  with  the  constitution 


11 
14  HaO  •  36  Si02, 

in  which  the  positions  marked  with  a  -f  are  either  direct  bonds  between 
the  Si-hexites  or  are  those  to  which  dibasic  or  sesquioxide-forming 
elements  may  be  attached,  by  means  of  this  constitutional  formula 
many  hitherto  puzzling  properties  of  the  "  glasses  "  may  be  explained. 

It  should  be  observed  that  in  this  formula  the  maximum  of 
OH-groups  is  shown.  A  series  of  acids  with  fewer  OH-groups  is 
theoretically  possible  ;  from  these  a  series  of  salts  can  be  produced 
as  in  the  case  of  the  complex  acids. 

The  following  lines  deal  with  some  properties  of  "  glasses  "  which 
are  explicable  by  means  of  this  theory  : 

1.  Schott478  has  examined  "  best  Thuringian  glass  "  with  a  com- 
position corresponding  to 

8  Na20  •  KaO  •  4  CaO  •  A12O,  •  36  Si02 
Calcd.      16.05      3.04      7.25       3.30        70.36 
Found     16.01       3.38      7.24       3.00       69.02     (0.42  Fe203  and  0.26  MgO) 

in  a  threefold  manner,  viz  : 

(a)  After  two  years'  exposure  to  air, 

(b)  After  heating  to  100°  C.,  and 

(c)  After  heating  to  the  softening  point. 

The  glasses  were  carefully  cleaned  with  water,  alcohol  and  ether, 
dried  by  prolonged  standing  over  sulphuric  acid,  weighed  before  and 
after  treatment  with  water  and  finally  after  heating  in  an  air  bath  at 
150°  C.  The  loss  of  weight  was  calculated  to  milligrammes  per  sq.  cm. 

Experiment  I :  Loss  of  weight  in  water  3-5  mg. 

„      at  150°  C.  0-8  mg. 

After  heating  in  water  the  glass  appeared  to  be  unchanged,  but  after 
heating  in  an  air  bath  the  whole  surface  became  covered  with  very  fine 
cracks,  but  no  flakes  were  split  off. 

Experiment  II :  Loss  of  weight  in  water  2-5  mg. 

„      at  150°  C.  0-8  mg. 

The  cracks  produced  in  the  air  bath  were  very  fine  and  could  scarcely 
be  seen  with  the  naked  eye. 

Experiment  III :  Loss  of  weight  in  water  1-8  mg. 

„      at  150°  C.  0-6  mg. 
In  this  case  no  cracks  could  be  observed  even  with  a  lens. 


THE   CONSTITUTION   OF  GLASSES,   ETC. 


239 


From  the  results  of  these  experiments  it  follows  that  the  constitu- 
tion of  the  glasses  tested  must  differ,  and  it  should  be  specially  noted 
that  heating  this  glass  to  its  softening  point  had  notably  improved  its 
quality,  as  is  shown  by  Experiment  III.  If  it  is  assumed  that  the 
dibasic  elements  and  the  sesquioxide  are  strongly  bound,  but  that  the 
alkali-atoms  are  labile,  the  following  isomers  of  the  original  formula 
may  be  conceived  ;  these  appear  to  confirm  the  three  foregoing 
experiments  : 


=Na, 


=Na2 
=Ca 


=Ca 


=Na, 


NaaNaaNaa 
B. 


NaaNa3Naa 
II      II      II 

K-XVS 

Si  I  Si  I  Si 
Ca= 


Naa= 


faaNaaNaa 
C. 


It  is  very  probable  that,  in  Experiment  III,  the  compound  A  is 
formed,  as  this  has  a  symmetrical  distribution  of  the  atoms  in  the 
molecule  which  would  account  for  its  greater  stability  than  the 
compounds  B  and  C. 

It  is  here  assumed  that  on  storing  or  heating  the  glasses  examined, 
only  the  alkali-atoms  change  places,  the  dibasic  and  Al-atoms  not 
being  affected.  This  assumption  is  justified  by  the  fact,  proved  by 
Weber,  that  very  little  depression*  is  shown  by  thermometer  glasses 
which  contain  potassium,  but  no  sodium.  If  this  depression  is  due  to  a 

*  When  some  kinds  of  glass  are  used  in  the  manufacture  of  thermometers,  these 
instruments  are  found,  in  course  of  time,  to  indicate  lower  temperatures  than  they 
should  do.  This  is  referred  to  as  the  "depression"  of  the  thermometer;  it  is  com- 
monly understood  to  be  due,  in  some  way,  to  the  chemical  composition  of  the  glass 
employed. 


240  CONSEQUENCES   OF  THE   H.P.   THEORY 

rearrangement  of  the  alkali-atoms  within  the  molecule,  those  glasses 
which  contain  sodium,  but  no  potassium,  should  show  no  depression  at 
all.  Experiments  made  by  Schott480  show  that  this  is  actually  the 
case. 

Thus,  glass  wrhich  contains  unmixed  alkali  (i.e.  a  pure  potash-lime 
glass)  when  used  for  thermometers  shows  a  much  smaller  error  owing 
to  changes  in  volume  than  a  glass  containing  mixed  alkalies  (i.e.  con- 
taining both  potash  and  soda).  Thus,  a  glass  which  contains  unmixed 
alkali745  showed,  after  a  given  time,  a  depression  of  only  0-04,  whilst 
a  glass  containing  mixed  alkali  had  a  tenfold  depression,  viz.  0.40. 

It  is  a  well-known  fact  that  thermometers  made  of  glass  containing 
both  potash  and  soda  are  erroneous  on  account  of  this  depression, 
whilst  those  made  of  potash  alone  are  quite  satisfactory  ;  this  was  first 
pointed  out  by  Weber  in  a  lecture  before  the  Prussian  Academy  of 
Science,  in  December,  1883. 

2.  It  is  a  well-known  fact  that  the  behaviour  of  various  kinds  of 
glass  under  the  heat  of  a  glass-blower's  lamp  varies  greatly  :  one 
kind  of  glass  (window  glass)  turns  matt  and  rough  shortly  after  it  has 
become  hot,  whilst  the  glass  made  in  the  Thuringian  Forest  can  with- 
stand repeated  heating  and  cooling,  and  may  be  blown  into  various 
shapes  and  re-melted  without  showing  any  signs  of  physical  change. 

Schott's481  experiments  on  Thuringian  glass  have  shown  that  it  has 
the  following  composition  : 

8.25  Na20  •  1.25  K20  •  0.25  MgO  •  4.25  CaO  •  A1203  •  36  SiO, 
Calcd.    16.21  3.72  0.37  7.54  3.23      68.93 

Found    16.01  3.38  0.27  7.38  3.38      67.74 

An  analysis  of  the  sand  used  in  its  manufacture  showed  : 

SiOa     A1203     Fe203     CaO     MgO     K20     Na20 
91.38      3.66        0.47       0.31     Trace     2.99        0.50 

Schott  therefore  assumed  that  this  glass  owes  its  valuable 
properties  to  the  alumina  it  contains,  this  being  derived  from  the  sand. 
He  has  confirmed  this  by  preparing  various  glasses  synthetically  from 
pure  quartz  to  which  various  quantities  of  alumina  were  added,  and 
found  that  the  latter  enabled  the  glass  to  be  worked  satisfactorily 
in  the  blower's  lamp  whilst  the  former  left  much  to  be  desired.  The 
value  of  alumina  has  also  been  confirmed  on  the  large  scale  ;  the 
addition  of  felspar  or  alumina  to  a  glass  mixture  invariably  improved 
the  working  qualities  of  the  glass. 

Seger746,  also,  made  exact  experiments  on  the  action  of  alumina  in 
glass  mixtures,  and  has  shown  that  it  increases  the  fusibility  of  the 
mixture  and  that  the  tendency  to  de vitrify  is  reduced.  Weber,  in  an 
exhaustive  treatise  on  "  Depression  Phenomena  in  Thermometers," 
has  stated  that  alumina  is  highly  important  in  the  manufacture  of 
glass  :  it  increases  the  fusibility  and  makes  it  easier  to  work. 

Schott  has  also  repeatedly  observed  that  the  tendency  to  crystallise 
or  devitrify,  shown  by  many  glasses  with  a  high  percentage  of  alkaline 


THE   CONSTITUTION   OF   GLASSES,   ETC.  241 

earths,  may  be  diminished  by  the  addition  of  alumina.  This  peculiar 
property  of  small  amounts  of  alumina  (2%  to  3%)  is  readily  understood 
in  the  light  of  the  H.P.  theory  of  the  constitution  of  glasses  ;  it  is  due 
to  the  bonding  of  the  silicon  hexites  by  the  Al-atoms.  Definite  com- 
plexes are  formed  and  may  be  conveniently  termed  y-complexes. 

The  presence  of  very  small  proportions  of  one  substance  in  another 
has  frequently  a  very  marked  effect  on  the  latter.  Thus,  Marignac484 
has  shown  the  enormous  influence  of  2  per  cent,  of  silica  in  silico- 
tungstates  ;  W.  Asche485  and  Parmentier  have  shown  the  equal 
importance  of  2  per  cent,  of  silica  in  the  silico-molybdates,  and  it  is 
very  probable  that  the  small  amounts  of  Ce203  in  the  rare-earths  used 
for  gas-mantles,486  phosphoric  acid  in  the  blood,  and  carbon,  tungsten 
and  other  "  impurities  "  in  steel  play  a  highly  important  part  in  the 
characteristics  of  these  substances. 

3.  Forster482    and     Kohlrausch483    have     independently    proved 
experimentally  that  glass  is  attacked  by  pure  water  more  strongly 
than  by  acids.    Forster  has  also  found  that  a  given  glass  will  lose  the 
same  weight  when  treated  with  sulphuric,  hydrochloric,  nitric  or  acetic 
acid,  of  either  one-thousandth  of  the  normal,*  or  ten  times  the  normal 
strength.     With  concentrated  acids,  Forster  found  the  action  to  be 
weaker  than  with  more  dilute  ones. 

This  property  may  be  explained  in  the  light  of  the  H.P.  theory,  as 
follows  :  The  water  causes  primary  alkali  to  become  separated  from  the 
molecule,  and  this,  to  some  extent,  reacts  in  a  secondary  manner  on  the 
hexite  and  partially  converts  it  into  pentite,  as  the  authors  of  the 
present  volume  have  frequently  observed  in  studying  the  complex 
salts.  With  acids,  on  the  contrary,  only  the  acid-water  reacts  and 
causes  a  partial  separation  of  the  alkali  in  the  glass.  This  alkali  is  at 
once  neutralised  by  the  acid  and  so  is  prevented  from  having  any 
secondary  action.  In  this  manner  the  more  powerful  action  of  water, 
as  compared  with  acids,  may  be  explained. 

4.  The  cause  of  the  phenomenon  known  as  "  devitrification  "  was, 
until  quite  recently,  extremely  puzzling  and  has  not  been  ascertained 
with  certainty.    For  instance,  Zulkowski  considered  that  devitrifica- 
tion is  due  to  the  presence  of  subsidiary  silicates.    Thus,  a  glass  made 
from  a  mixture  corresponding  to  the  formula  : 

9  Na20  +  10  CaO  +  60  SiOa, 
is  stated  by  Zulkowski  to  be  : 

8  (CaO  •  Na20  •  6  SiO2)  +  2  (CaO  •  4  Si02)  -f  Na20  •  4  Si02 
True  glass.  Subsidiary  silicates. 

The  glass  is  thus  regarded  by  Zulkowski  as  composed  of  8  molecules 
of  normal  glass  with  2  molecules  of  calcium  tetra-silicate  and  1  mole- 

*  "Normal  acid  "  is  of  such  a  strength  that  1  c.c.  of  it  will  exactly  neutralise  0-040 
gramme  of  NaOH  or  0-053  gramme  of  Na2CO3,  hence  1  c.c.  of  "  one- thousandth  normal  " 
or  milli-normal  acid  will  exactly  neutralise  0-000040  gramme  NaOH  and  1  c.c.  of  "  ten 
times  normal  "  acid  will  neutralise  0-400  gramme  NaOH  or  the  equivalent  weight  of 
any  other  alkali. 


242  CONSEQUENCES  OF  THE   H.P.   THEORY 

cule  of  sodium  tetra-silicate.    These  subsidiary  silicates  are,  according 
to  Zulkowski,  the  cause  of  devitrification. 

In  the  opinion  of  the  authors  of  the  H.P.  theory,  the  experiments 
of  M.  Groger748  throw  a  special  light  on  the  subject  of  devitrification 
and  lead  to  the  true  causes  of  this  phenomenon.  Groger  examined  a 
devitrified  bottle  glass  made  in  the  works  of  the  Austrian  Glasshiitten- 
gesellschaft  at  Aiissig.  It  consisted  of  crystalline  nodules  which,  on 
fracture,  were  composed  of  radial  fibres  of  a  matt  greenish-white  tint. 
In  these  nodules  completely  transparent,  dark  green  masses  are 
embedded.  Groger  analysed  both  the  transparent  masses  and  the  less 
transparent  devitrified  portions  and  found  that  their  chemical  com- 
position was  identical  and  corresponded  to  the  general  formula  : 

2.5  R2O  •  4.5  RO  •  A1203  •  15  Si08, 
0.25  KS0  2.25  Na2O  0.25  MgO  3.5  CaO  0.5  MnO  0.25  FeO  A120,  15  SiO, 

Theory : 
1.64  9.75  0.70  13.70        2.48  1.24  7.13     63.36 

Found  in  devitrified  portion : 
1.52  9.76  0.61          13.38        2.49          1.39  7.73    63.79 

Found  in  transparent  portion : 
1.45  9.78  0.73  12.81         2.47  1.39  7.42     64.39 

In  this  manner  Groger  confirmed  the  statement  of  Pelouze  that  the 
devitrified  portions  are  of  the  same  composition  as  the  glass  itself,  and 
also  that  of  Benrath  in  which  the  errors  in  the  view  previously  held,  that 
a  devitrified  glass  is  more  siliceous  than  a  normal  glass,  were  exploded. 

Groger  also  investigated  the  physical  and  chemical  properties  of 
both  portions  in  order  to  ascertain  the  cause  of  the  devitrification. 
He  showed  that  the  two  portions  differed  considerably  in  both  physical 
and  chemical  properties.  For  instance,  the  transparent  portion  is 
much  more  fusible  than  the  devitrified  portion. 

Again,  when  treated  with  concentrated  hydrochloric  acid  the 
devitrified  portion  was  almost  dissolved  completely,  whilst  the 
transparent  portion  remained  unattacked.  From  this,  Groger  con- 
cluded that  the  devitrified  portion  consisted  of  two  different  substances 
and  endeavoured  to  separate  them  by  digesting  for  twelve  hours  with 
concentrated  hydrochloric  acid.  Both  portions — the  soluble  and  the 
insoluble — were  analysed  and  conformed  to  the  following  formulae  : 
For  the  soluble  portion  : 

10.25  RO  •  0.75  RaO  •  0.12  Si02. 
For  the  insoluble  portion  : 

1.75  RO  -  2.25  R,0  •  A1203  •  12  Si02. 
These  figures  were  deduced  from  the  following  data  : 

0.25  FeO    9.5  CaO  0.5  MgO  0.75  Na20  12  SiOa 
Theory    1.35         39.80        1.49         3.48  53.88 

Found     1.16         39.30        1.33        3.57  52.89    0.27  MnO     0.36  K20 


THE   CONSTITUTION  OF  GLASSES,  ETC. 

0.25  FeO  0.25  MnO  CaO  0.25  MgO  2  Na80  0.25  K,0  A120,  12  SiO, 
Theory    1.67          1.65          5.20    0.92          11.53        2.18  9.48     67.37 

Found     1.88         2.60         5.83    0.73         11.27        1.28          9.44    66.97 

In  the  light  of  the  H.P.  theory,  the  devitrification  of  this  mass  is 
readily  explained.  The  clear  portion  consists  of  a  perfectly  stable 
penta-compound  which,  in  time,  parts  with  a  simple  silicate  and  is 
converted  into  a  hexa-compound.  Groger  interpreted  his  results  in  a 
similar  manner  and  considers  that  the  devitrification  is  due  to  an 
unmixing  of  the  glassy  mass.  In  other  words,  devitrification  is  not  a 
molecular  change,  such  as  occurs  when  amorphous  arsenic  acid  is 
converted  into  the  crystalline  modification  (Pelouze),  but  the  con- 
version of  an  unstable  compound  into  a  stable  one  by  the  separation  of 
a  definite  constituent.  This  conclusion  agrees  completely  with  the 
interesting  results  obtained  by  O.  Schott749  in  the  microscopical 
examination  of  numerous  de vitrified  products.  Schott  found  that 
de vitrified  glasses  contain  crystals  of  wollastonite  (calcium  silicate), 
and  the  existence  of  this  substance  as  an  integral  part  of  devitrified 
glass  is  shown  in  the  above  analysis. 


As  far  back  as  the  year  1900,  Zulkowski741  endeavoured  to  refer 
the  properties  of  glass  to  its  chemical  constitution  and  found  that,  at 
that  time,  the  only  properties  to  which  glass  manufacturers  and  others 
paid  much  attention  were  of  an  aesthetic  nature,  such  as  the  shape  of 
the  articles  made,  and  the  colour,  transparency  and  light  refractivity 
power  of  the  glass.  The  chemical  properties  of  glass,  i.e.  its  resistance 
to  weather,  water  and  various  chemicals,  had  scarcely  been  studied  at 
all,  and  Zulkowski  very  wisely  pointed  out  that  many  articles  of  a 
domestic  or  aesthetic  nature,  to  say  nothing  of  the  innumerable 
technical  and  optical  articles  made  of  glass,  and  those  used  in  the 
experimental  sciences,  require  that  glass  should  possess  not  only  certain 
physical  properties,  but  the  still  more  important  chemical  ones,  and 
yet  the  study  of  the  latter  has  been  almost  entirely  neglected. 

Nevertheless,  the  chemical  structure  attributed  to  glass  by  Zul- 
kowski does  not  sufficiently  explain  the  various  properties  which  have 
been  mentioned  in  the  present  chapter,  whereas  the  H.P.  theory  does 
explain  them  satisfactorily. 


The  Chemical  Constitution  of  Coloured  Glasses 

Coloured  glasses  of  the  most  varied  tints  may  be  prepared  by 
means  of  suitable  preparations  of  copper,  silver,  gold  and  kon,  and 
attempts  to  learn  the  chemical  constitution  of  these  glasses  have  been 
made  by  numerous  chemists.  Zulkowski,  for  instance,  regards  them 
as  mixtures  of  various  silicates,  one  of  which  contains  the  colouring 


244 


CONSEQUENCES  OF  THE   H.P.   THEORY 


oxide.    Thus,  according  to  him,  the  ferrous  oxide  in  a  glass  is  contained 
in  a  silicate  of  the  following  formula  : 

/°\ 

SinOSn_i<          /Fe  or 


SinO 


in— 1 


-ONaNaO 


S0  •  Fe  •  0 


>Sin02n_i 


The  constitution  of  coloured  glasses  is  of  extreme  importance,  both 
scientifically  and  artistically.  The  most  widely  adopted  view  is  that 
glasses  are  colloids  and  that  the  colouration  is  of  a  colloidal  nature. 
That  the  source  of  the  colour  of  glasses  is  analogous  to  that  of  organic 
compounds  does  not  appear  to  have  been  suggested,  and  it  is  therefore 
of  great  interest  to  consider  it  with  the  assistance  of  the  H.P.  theory. 
When  this  is  done  the  surprising  conclusion  is  reached  that  coloured 
glasses  possess  a  structure  analogous  to  that  of  the  organic  dye-stuffs 
and  that  the  colour  of  the  glass  is  due  to  the  chromophore  groups  and 
salt-forming  groups  in  accordance  with  the  theory  which  Witt  devised 
for  organic  dye-stuffs. 

Glasses  do  not  belong  to  a  single  class,  but,  as  their  analyses 
indicate,  to  several  classes  of  compounds,  some  of  which  are  simple 
and  others  highly  complex.  This  may  be  readily  observed  in  the 
following  types  of  glasses  : 


8  R20  •  6  RO  •  36  SiO, 
A. 


8  R20  •  2  RO  •  A120S  •  36  SiO, 
B. 


4  R20  •  RO  •  6  B208  •  24  SiO, 
C. 


(3  R20  •  7.5  B208  •  6  SiO,)2  etc, 

D. 


THE   CONSTITUTION  OF  GLASSES,  ETC.  245 

In  the  positions  marked  -f  not  only  acid  groups,  but  also  groups 
of  metallic  oxides  (in  either  -ous  or  -ic  form)  may  enter.  The  intro- 
duction of  such  acid  or  metallic  oxide  groups  may  conveniently  be 
termed  central  acidising  or  central  metallising  and  the  groups  them- 
selves may  be  termed  centralisers. 

All  these  centralisers  have  an  important  influence  on  the  rings,  as 
will  be  shown  later.  At  the  moment,  however,  the  metallic  central- 
isers are  the  most  interesting,  as  they  give  to  compounds  containing 
them  the  property  of  absorbing  certain  selected  rays  of  light,  i.e. 
the  metallic  centralisers  are  excellent  chromophores. 

The  structure  of  these  chromophore  groups  may  be  explained  as 
follows  :  The  positions  marked  +  in  the  foregoing  structural  formulae 
are  supposed,  for  the  moment,  to  be  occupied  by  CuO.  One  of  these 
positions  may  then  be  represented  by  : 


Si 

/\ 
O     0 


Cu 

/\ 

O     0 

V 

Si 


This  group  may  lose  oxygen  and  so  be  converted  into  the  group 


B. 


246  CONSEQUENCES  OF  THE  H.P.  THEORY 

On  further  reduction,  group  B  forms  the  group  : 

Si- 
O 

Cu 
Cu 
O 

Si— 

c. 

Group  C  can  also  part  with  oxygen  or  copper. 

Group  B  is  the  chromophore  group  which,  on  reduction,  forms  the 
leuco-group  C.  The  latter,  on  oxidation,  again  forms  the  chromophore 
group  B.  If,  during  this  re-oxidation,  a  little  of  the  separated  metal 
remains  unoxidised,  a  coloured  glass  will  be  obtained  in  which  small 
quantities  of  free  metal  occur  simultaneously  with  the  chromophore 
group. 

Decolouration  by  reduction  and  re-colouration  by  oxidation  have 
been  repeatedly  observed  in  organic  dye-stuffs.  It  was  first  pointed 
out  by  C.  Grabe  and  C.  Liebermann750,  who  found  that  all  the  coloured 
organic  compounds  which  they  examined  became  colourless  on 
reduction.  The  reduction  may  cause  the  direct  addition  of  hydrogen 
without  the  loss  of  any  element  from  the  molecule,  or  it  may  be  effected 
by  the  simple  removal  of  oxygen  from  the  compound. 

Besides  the  chromophore  groups,  the  side-chains  have  also  an 
important  influence  on  the  colour.  In  coloured  glasses  these  side- 
chains  are  of  a  basic  nature,  and,  in  accordance  with  Witt's  theory, 
these  glasses  should  be  classified  as  "  basic  colours." 

Witt's  Theory. — According  to  0.  N.  Witt751,  the  colour  of  aromatic 
compounds  is  due  to  the  simultaneous  presence  of  a  colour  group  or 
chromophore,  and  of  a  salt-forming  group.  The  chromophore  is  more 
active,  i.e.  it  produces  a  stronger  colour,  when  the  dye  is  a  salt  than 
when  it  is  in  the  state  of  either  a  free  acid  or  a  free  base. 

In  organic  dyes  and  colours,  the  colour-substances  must  contain 
chromophore  centralisers  such  as  are  required  for  coloured  silicates  by 
the  H.P.  theory.  Such  colour-substances  are  typified  by  some  dyes 
containing  the  so-called  triphenylmethane  group.  The  oxidation 
products  of  the  compounds  : 

/C,H4  •  NHZ  xC6H4  •  NH2 

eC«H4  •  NH2  C(OH)^C8H4  •  NH2 

\C6H4  •  NH8  \C,H3(CH8)  •  NH, 

Paraleucaniline.  Rosaniline. 


THE   CONSTITUTION   OF   GLASSES,  ETC. 

and  the  substances 


247 


C6H4  •  NHt 
NH2 
I  \C,H4  •  NH  •  HC1 


and 


/C,H4  -  NH, 
C— C,H4  •  NH2 
\CeH,CH8  -  NH  •  HC1 


are  basic  dyes  on  account  of  the  basic  groups,  though  the  materials 
from  which  they  are  prepared — paraleucaniline  and  rosaniline — are 
colourless.  The  structure  of  these  colours  may,  according  to  the  H.P. 
theory,  be  written  as  follows  : 


NH, 


NH, 


These  new  structural  formulae  are  in  as  complete  agreement  with 
the  properties  of  these  substances  as  the  ones  generally  seen  in  text- 
books and  have,  in  addition,  the  following  advantages  : 

1.  They  show   a   complete   analogy  with   the   coloured   glasses, 
inasmuch  as  both  the  organic  compounds  and  the  glasses  are  shown  to 
contain   chromophore   centralisers ;     in   the   former   case,   carbonic 
centralisers. 

2.  As  distinct  from  the  usual  structural  formulae,  the  new  ones 
show  definite  symmetry,  which  makes  the  new  formulae  more  probably 
correct  than  the  older  ones. 

3.  The  difficulties  connected  with  difference  in  behaviour  between 
the  central  ring  and  the  two  others  in  the  older  formulae  do  not  occur 
in  the  new  formulae,  as  in  the  latter  the  groups  are  arranged  differently. 
There  are  many  other  instances  in  which  this  difficulty,  encountered 
when  the  text-book  formulae  are  used,  is  avoided  by  the  employment 
of  the  new  formulae. 

With  the  assistance  of  the  H.P.  theory  in  combination  with  that  of 


248  CONSEQUENCES  OF  THE   H.P.   THEORY 

Witt,  the  possible  existence  of  the  following  coloured  glasses  containing 
copper  may  be  predicted  : 


Type 

A. 
B. 
C. 
D. 
E. 
F. 
G. 

I. 

8 
8 
8 

8 
8 

8 
8 

R20- 
R20- 
R2O- 
R20- 
R20- 
R20- 
R20- 

6  R'O 
10  R'O 
12  R'O 
16  R'O 
17  R'O 
nR'O 
nR'O 

•  3  Cu20 
•  3  Cu20 
•  3  Cu20 
•  3  Cu2O 
•  3  Cu20 
•  2  Cu20 
•  Cu20 

•  36  Si02 
•  36  Si02 
-  36  Si02 
•  36  Si02 
•  36  Si02 
•  36  Si02 
•  36  Si02 

H.     p(8  R20  •  nR'O  •  36  Si02)  +  q(8  R20  •  nR'O  •  Cu20  •  36  Si02) 

Type  II. 

A.  6  R20  •  4  R'O  •  Cu20  •  B203  •  36  SiO« 

B.  p(6  R2O  •  4  R'O  •  Cu20  •  B203  •  36  Si02)  +  q(6  R20  •  4  R'O  •  B203 

-  36  Si02) 

Type  III. 

A.  7  R20  •  7  R'O  •  CuaO  •  A1,O,  •  36  Si02  +  7  R20  •  7  R'O  •  A1203 

-  36  Si02  +  Cu, 

B.  p(7  R20  •  7  R'O  •  Cu20  •  A1203  •  36  Si02)  -f  q(7  R,0  •  7  R'O  •  A1203 

-  36  Si02)  -f-  rCua,  etc.  etc. 

These  three  types  of  glass  must  obviously  differ  in  their  properties. 
The  glasses  in  the  first  group  are  simple  silicates,  those  in  the  second 
group  are  the  Gamma  Complexes,  in  which  the  copper  is  more  strongly 
combined  than  in  group  I.  In  the  third  group  the  glasses  are  also 
Gamma  Complexes,  in  which  free  metallic  copper  occurs  in  addition  to 
the  copper  in  combination. 

[The  existence  of  coloured  glasses  containing  other  metals  in  place  of  copper  and 
of  a  completely  analogous  constitution  is  equally  possible.] 


The  H.F.  Theory  and  the  Facts 

Only  one  glass  in  the  first  group  mentioned  above  has  yet  been 
prepared,  namely  Porpora,*  which,  according  to  Zulkowski752,  corre- 
sponds to  the  formula  : 

8  R20  •  17  R'O  -  3  Cu20  •  36  Si02. 

*  Porpora  glass  is  defined  as  a  glass  which  has  a  rusty  red  colour  by  reflected  light 
and  a  purple-blue  colour  by  transmitted  light,  the  colour  being  due  to  a  small  proportion 
of  copper  added  to  the  batch. 


THE   CONSTITUTION   OF  COLOURED   GLASSES        249 

The  analysis  of  this  glass  when  re-calculated,  in  accordance  with 
formulae  suggested  by  the  H.P.  theory,  is  as  follows  : 

6.25  Na,O  1.75  K,O   4.5  CaO      10.5  PbO       IFeO  1  MnO  3Cu2O  36SiO2 

Theory  6.57         2.79         4.27         39.74         1.22  1.20  7-28  36.91 

Found    6.31         2.60         4.31         39.06         1.29  1.50  7.89  35.80 

Trace     A1203 

Zulkowski  has  also  analysed  a  glass  belonging  to  the  second  group 
and  known  commercially  as  Copper  Ruby.  This  analysis  corresponds 
to  the  formula  : 

6  R20  •  4  R'O  •  0.5  Cu20  •  B203  •  36  Si02 

3.25  K,O    2.75Na,O    O.SSnO      0.75MnO      1.75 PbO        ICaO       0.5Cu,0        B,0,  36SiOf 

Theory    9.10      5.07       1.99       1.59       11.62       1.67      2.12      2.08      64.76 

Found     9.11       5.13      2.16       1.91       10.71       1.52       1.63      2.53      64.80 

Traces  of  FeO  •  A1203  •  MgO 

Zulkowski  has  also  analysed  aventurine,  a  glass  belonging  to  the 
third  group.  Part  of  the  copper  in  aventurine  glass  is  in  the  free  state, 
but  if  all  the  copper  is  considered  to  be  in  combination  the  analysis 
corresponds  to  the  formula  : 

7  R,0  •  7  R'O  -  Cu,0  •  Al.O,  •  36  SiO, 

1.5  K,O      5.5Na,O      O.SPbO     0.25  FeO       5CaO      1.25  MgO       Cu,0          Al»0»          36SIO, 

Theory    4.19       10.15       3.22      0.53       8.33       1.49       4.25       3.03       64.71 
Found     4.46       10.22      3.07      0.68      8.74       1.57      4.90      2.16      64.52 

The  structural  formulae  of  these  glasses  when  arranged  in  accordance 
with  the  H.P.  theory  are  as  follow  : 

Porpora  glass 
323 

11  OL 

Si  I  Si    Si 


Cu2Cu2  Cu2 

I      I 


Si    Si 


Si 


"\/\/\/" 

II      II      II 
333 


250 


CONSEQUENCES   OF  THE   H.P.   THEORY 


Copper  Ruby  glass 
I      II      I 


Aventurine  glass 


Cu2 


II      II 


A  large  series  of  facts  which  have,  hitherto,  been  inexplicable  is  in 
complete  agreement  with  these  structural  formulae.  For  example  : 

(a)  On  comparing  the  structure  of  the  ruby  glass  with  that  of  the 
porpora,  it  is  clear  that  the  chromophore 

>Si— 0—  Cu2— 0— Si<' 

in  the  ruby  glass  is  in  the  first  y-complex,  whilst  the  corresponding 
chromophore  groups  in  the  porpora  glass  are  combined  with  a  simple 
polymerised  silicate. 

From  the  H.P.  theory,  a  masking  of  the  Cu20  in  copper  ruby  glass 
may  be  predicted,  i.e.  this  oxide  will  not  be  recognised  by  ordinary 
tests  so  readily  as  it  is  in  the  porpora  glass.  This  interesting  conse- 
quence of  the  theory  is  found  to  be  in  complete  agreement  with  the 
experimental  evidence. 

According  to  Rose  and  Hampe753,  cuprous  oxide  and  silver  nitrate 
react  as  follows  : 

3  Cu2O  -f  6  AgN03  4-  3  H20  =  2  Cu2H3N06  -j-  2  Cu(N08)a  +  6  Ag. 

Zulkowski752  used  this  reaction  in  his  studies  of  the  copper  ruby 
and  porpora  glasses  and  found  that  whilst  the  porpora  glass  effected 
a  separation  of  metallic  silver  in  accordance  with  the  equation,  the 
copper  ruby  glass  showed  no  such  separation,  even  after  many  weeks. 

(b)  From  the  structural  formulae  of  these  three  glasses  it  follows 
that  only  the  aventurine  contains  free  metallic  copper.    The  facts  fully 
confirm  this  consequence  of  the  theory.    For  example,  Wohler  found 


THE   CONSTITUTION  OF  COLOURED   GLASSES       251 

that  on  placing  this  glass  in  a  solution  of  mercuric  chloride  it  became 
white  and  copper  entered  into  solution — a  clear  sign  of  the  presence  of 
metallic  copper.  It  might,  of  course,  be  argued  that  cuprous  oxide, 
which  is  also  present  in  aventurine  glass,  would  produce  the  same 
result,  but  this  argument  has  been  met  by  Zulkowski752,  who  treated 
the  powdered  glass  with  an  ammoniacal  solution  of  copper.  In  the 
presence  of  metallic  copper  the  reaction  with  this  solution  would  be 

Cu  +  CuO  =  Cu20, 

and  the  solution  must  be  decolourised.  Zulkowski  placed  a  weighed 
quantity  of  finely  powdered  aventurine  glass  in  a  test  tube  and  then 
added  an  ammoniacal  solution  of  copper  sulphate  in  such  an  amount 
that  the  metal  in  it  was  equal  to  one-quarter  of  the  copper  in  the  glass. 
The  tube  was  then  sealed  and  heated  on  a  water  bath.  After  15  hours 
the  deep  blue  colour  of  the  solution  was  entirely  discharged,  thus 
proving  beyond  all  doubt  that  aventurine  glass  contains  free  copper. 

Zulkowski  has  also  shown  by  similar  tests  that  porpora  and  copper 
red  glasses  contain  no  free  copper.  In  the  case  of  porpora  the  colour 
of  the  solution  was  not  affected  in  the  least  nor  was  the  tint  of  the  glass 
changed,  even  after  three  years.  The  test  was  not  so  prolonged  with  the 
copper  red  glass,  but  even  after  several  weeks  the  colour  of  the 
solution  was  not  changed  in  the  least.  These  tests  show  beyond  all 
question  that  the  porpora  and  copper  red  glasses  contain  no  free 
metallic  copper,  but  that  it  is  present  in  aventurine  glass.  They  also 
shatter  the  opinion,  commonly  held,  that  the  colour  of  the  two  glasses 
first  named  is  due  to  their  ability  to  dissolve  metallic  copper  and  re- 
tain it  in  solution  in  its  metallic  state. 

(c)  The  structural  formulae  of  porpora,  copper  red  and  aventurine 
glasses  also  show  that  the  colour  is  due  to  a  definite  chromophore 
group  and  not  merely  to  dissolved  cuprous  oxide  as  is  frequently 
stated.  The  investigations  made  by  Seger754  on  coloured  cuprous 
glasses  are  in  full  agreement  with  this  consequence.  This  investigator 
showed  that  an  alternately  reducing  and  oxidising  atmosphere  is 
necessary  in  the  production  of  these  glasses,  and  that  the  difficulties 
in  manufacture  were  not  so  much  due  to  the  glass  itself  as  to  the  correct 
atmosphere  in  the  furnace.  Seger  found  that  the  same  glass-mixture 
would  produce  all  shades,  from  black,  through  brown,  to  bright  red  or 
yellowish  green,  and  that  different  parts  in  the  same  melt  would  vary 
enormously  in  colour,  according  to  the  nature  of  the  gases  which 
entered  the  crucible  ;  that  some  melts  would  be  of  good  colour  whilst 
others  of  the  same  batch  would  be  quite  devoid  of  red  and  would, 
instead,  be  black  or  grey. 

All  these  variations  show  that  red  glass  must  have  a  definite  chemical 
constitution,  that  it  must  contain  certain  chromophore  groups,  and  not 
be  merely  a  solution  of  copper  or  cuprous  oxide.  Seger  confirmed 
this  view  when  he  added  1  percent,  of  cupric  oxide  to  a  glass  correspond- 
ing in  composition  to 

3  Na20  •  3  CaO  •  3  B203  •  15  Si02. 


252 


CONSEQUENCES   OF  THE   H.P.   THEORY 


This  mixture  was  placed  in  a  porcelain  crucible  which  was  then  placed 
in  a  platinum  one.  The  platinum  crucible  was  fitted  with  a  porcelain 
lid  through  which  protruded  a  porcelain  tube  of  small  bore.  On 
heating  the  crucible  to  400°  to  500°  and  passing  a  stream  of  hydrogen 
or  carbon  monoxide  through  the  tube,  the  copper  oxide  was  reduced, 
but  the  glass  did  not  fuse  ;  it  merely  formed  a  red  clinker.  On  raising 
the  temperature  to  950°  and  continuing  the  stream  of  reducing  gas,  the 
metallic  copper  previously  formed  disappeared,  the  particles  dissolving 
in  the  molten  glass,  and  the  colour  of  the  glass  changed  from  red  to  a 
greenish  grey.  On  powdering  this  grey  glass  and  re-heating  with 
white  glass  to  which  a  little  oxidising  agent,  such  as  1  per  cent,  iron 
oxide,  tin  oxide  or  a  sulphate  like  gypsum,  had  been  added  and  sub- 
stituting a  stream  of  air  for  the  former  reducing  gas,  Seger  obtained 
a  red  glass. 

He  explained  this  phenomenon  by  supposing  that  the  oxygen  con- 
verted the  black  metallic  copper  *  into  red  cuprous  oxide  and  the  latter 
gave  the  glass  its  red  colour.  Seger  suggested  the  three  following 
equations  as  showing  what  occurred  with  different  oxidants  : 

2  Cu  +  Fe203  =  Cu20  +  2  FeO 
2  Cu  +  Sn02   =  Cu20  +  SnO 
2  Cu  +  S03     =  Cu20  +  S02. 

The  correctness  of  the  last  equation  is  confirmed  by  the  voluminous 
development  of  gas  during  the  fusion. 

The  red  glass  thus  formed  may  clearly  be  represented  by  the 
following  formula  : 


B      Si    >— Cu2— <    Si      B 


in  which  it  is  assumed  that  only  a  portion  of  the  glass  contains  the 
chromophore  shown.  Otherwise,  the  proportion  of  cuprous  oxide  would 
have  to  be  higher  than  that  actually  present. 

The  phenomena  observed  by  Seger  are  in  complete  conformity 
with  the  consequences  of  the  application  of  the  H.P.  theory  to  coloured 
glasses. 

(d)  It  has,  hitherto,  been  impossible  to  understand  why  coloured 
glasses  should  contain  such  small  quantities  of  free  metallic  con- 
stituents. Not  only  can  this  fact  now  be  explained,  but  it  is  a  direct 
consequence  of  the  H.P.  theory. 

*  Strictly,  this  is  not  metallic  copper  at  all,  but  the  leuco-compound  or  the  reduced 
leuco-compound  (p.  246). 


ARE   GLASSES  SOLID   SOLUTIONS?  253 

(e)  According  to  the  theory  there  is  a  definite  maximum  for  the 
metallic  constituents  to  which  the  colour  of  glasses,  etc.,  is  due.  This 
maximum  is  not  exceeded  in  the  glasses  mentioned  on  preceding  pages, 
and  further  investigations  will  only  show  that  it  must  not  be 
exceeded. 

It  is  highly  probable  that  glasses  containing  silver  and  gold  are 
completely  analogous  to  those  containing  copper,  but  to  prove  this  it 
will  be  necessary  to  re-calculate  the  analyses  of  these  glasses  and  to 
consider  their  characteristics  and  properties  with  the  aid  of  the  H.P. 
theory. 

In  reviewing  the  German  edition  of  the  present  work,  C.  Desch736 
urged  that  the  use  of  "  definite  formulae  "  for  glass  and  porcelain  is 
unjustifiable.  This  is  not  surprising,  as  Desch  has  so  strongly  com- 
mitted himself  to  the  view  that  cements,  glasses  and  porcelains  are 
all  "  solid  solutions."  Of  various  theories,  that  one  is  most  likely  to  be 
correct  which  explains  the  most  facts  and  permits  the  prediction  of 
the  most  properties,  and  on  this  basis  the  H.P.  theory,  like  all 
others,  must  be  judged.  The  authors  of  the  H.P.  theory  have  never 
suggested  that  the  structural  formulae  they  assign  to  various  substances 
are  in  any  sense  "  final,"  and  they  readily  admit  that  they  must  be 
altered  whenever  other  formulae  which  correspond  with  more  proper- 
ties are  discovered.  Meanwhile,  the  fact  that,  at  present,  they 
explain  more  properties  than  any  other  formulae  yet  devised  is  a 
sufficient  reason  for  the  formulae  deduced  from  the  H.P.  theory. 
Moreover,  so  far  as  the  authors  of  this  theory  are  aware,  there  is,  at 
present,  no  real  ground  for  doubting  the  correctness  of  their  conclusions. 
On  the  other  hand,  what  good  does  it  do  to  assume  that  glasses  are 
mixtures  or  solid  solutions  ?  Such  a  view,  which  is  held  by  many 
chemists,  including  all  the  chief  critics  of  the  H.P.  theory,  does  not  in 
any  way  advance  the  cause  of  science,  because  it  fails  to  explain  more 
than  a  very  small  proportion  of  the  facts,  whilst  an  enormously  large 
number  of  them  are  fully  explicable  in  accordance  with  the  H.P. 
theory.  Under  these  circumstances,  is  it  too  much  to  say  that  the 
deductions  from  the  H.P.  theory  approximate  far  more  closely  to  the 
true  structure  of  the  substances  concerned  than  do  the  "  mixture  " 
and  "  solid  solution  "  hypotheses  ? 

It  should  be  observed  that  in  this  volume  the  authors  have  made 
no  attempt  to  show  that  all  commercial  glazes,  glasses  and  porcelains 
are  definite  chemical  individuals,  though,  without  doubt,  many  of  them 
are  such.  In  the  following  pages  the  analyses  of  a  number  of  glasses, 
glazes,  and  porcelains  have  been  calculated  into  the  molecular  form, 
those  materials  being  selected  which,  on  account  of  their  excellent 
physical  and  other  properties,  appeared  likely  to  consist  of  definite 
chemical  compounds.  This  calculation  of  the  formulae  should  prove 
of  value  in  the  further  study  of  these  materials. 


254 


CONSEQUENCES  OF  THE   H.P.   THEORY 


Formulae  of  Glasses,  Glazes,  and  Porcelains 

The  following  analyses   of  three   Jena   glasses   are   taken  from 
Hovestadt's  book  on  the  subject : 

(a)  Jena  glass  3  III  has  the  following  composition  : 

3  Na2O  •  3  CaO  •  0.25  A1203  •  0.75  B203  •  12  Si02 
Calcd.      16.07       14.52        2.20  4.53          62.67 
Found         16          16             2  4  62 

(b)  Jena  glass  6  III  has  the  following  composition  : 

3  Na20  •  0.5  K20  •  0.75  A1203  •  0.25  B208  •  15  SiO, 
Calcd.    15.18        3.84          4.17  2.84  73.97 

Found      15  5  5  2  73 

(c)  Jena  glass  13  III  has  the  folio  whig  composition  : 

1,5  K20  •  2.5  ZnO  •  B2O3  •  10  Si02 
Calcd.      13.86        19.91        6.86      59.37 
Found       15  20  7  58 

(d)  The  composition  of  a  glass  highly  prized  for  champagne  bottles, 
analysed  by  Maumene487,  is  : 

4  CaO  •  2  Na20  -  0.25  K20  •  0.25  A1203  •  0.75  Fe203  •  12  Si02 
Calcd.     18.05      9.98  1.89  2.05  9.66  58.37 
Found     18.60      9.90           1.80            2.10             8.90  58.40 

According  to  F.  Fischer488,  the  composition  of  the  glaze  ordinarily 
used  for  porcelain  corresponds  to  the  formula  : 

RO  •  1  to  1.25  A12O3  •  10  to  12  Si02. 

The  folio  wing  Tables  have  been  calculated  from  various  analyses  of 
porcelain  and  porcelain  glazes  published  by  Seger489. 

I.  Formulae  of  Porcelain  Glazes 


1 

SiO,  |  TiO,  |  Al,0, 

Perec 
Fe,0« 

ntage  o 
CaO 

I 

MgO 

K,0 

NajO 

HaO 

Mole 

E,O|E,O, 

culea 
EO, 

H,0 

Sources  of  glazes 

1. 

73.24 

— 

13.97 

0.31 

2.57 

0.51 

4.81 

1.71 

3.83 

2.0 

2 

18 

3.0 

Berlin         porcelain 

glaze   (old,   prob- 

ably of  Dr.  Eis- 

ner's period). 

2. 

76.11 

— 

14.61 

0.66 

1.44 

0.42 

2.99 

3.03 

1.23 

1.5 

2 

18 

1.0 

Pegmatite         glaze 

from    L.    Sazerat 

in  Limoges. 

3. 

74.99 

— 

14.80 

0.37 

1.09 

0.36 

4.31 

3.49 

0.65 

2.0 

2 

17 

0.5 

Porcelain           glaze 

from    Limoges 

(per  Held  &  Co., 

Mayence). 

4. 

64.96 

— 

12.74 

0.80 

8.78 

— 

1.95 

2.30 

9.19 

3.5 

2 

17 

8.0 

Japanese         porce- 

lain   glaze    from 

Arita.    No.  2. 

5. 

61.97 

— 

12.92 

0.39 

9.59 

— 

4.17 

1.12 

9.91 

3.5 

2 

16 

8.5 

Japanese         porce- 

lain   glaze    from 

Arita.    No.  1. 

6. 

64.88 

1.39 

14.33 

1.39 

10.09 

1.55 

5.61 

— 

— 

4.5 

2 

15 

— 

Chinese         celadon 

(FeO) 

glaze. 

FORMULA   OF  PORCELAIN  GLAZES 

II.  Formula  of  Porcelains490 


255 


No 

SiO, 

Al,0, 

Per 
Fej03 

centage 
MgO 

of 
K,0 

NaaO 

H2O 

E4O 

Mole 
R.O, 

culea 
SiOa 

HaO 

Source  of  the  Porcelains 

1. 

63.95 

25.59 

0.69 

0.54 

2.07 

0.98 

6.62 

0.5 

3 

12 

4.0 

Soci6te  anonyme  de 

Hal  (Belgium). 

2. 

63.07 

24.67 

0.59 

0.40 

4.25 

— 

7.00 

0.5 

3 

12 

4.5 

Berlin  porcelain,  187  7 

Alk. 

3. 

63.48 

25.00 

0.51 

1.06 

2.26 

1.19 

6.76 

0.5 

3 

12 

4.0 

A.    Hache  &  Pepin, 

CaO 

Schalleur,  Vierzon. 

4. 

60.53 

26.37 

0.75 

0.69 

2.95 

1.44 

6.39 

0.5 

3 

12 

4.0 

L.  Sazerat,  Limoges, 

CaO 

body  for  heavy 

porcelain. 

5. 

60.42 

26.47 

0.52 

1.37 

2.75 

1.60 

7.19 

1.0 

3 

12 

5.0 

L.  Sazaret,  Limogea, 

CaO 

ordinary  body 

6. 

76.75 

18.44 

1.17 

0.02 

4.23 

0.17 

— 

0.5 

3 

18 

— 

Japan  IV,  Biscuit  of 

CaO 

egg-shell  porcelain. 

7. 

71.31 

19.74 

0.73 

0.17 

4.04 

0.1 

4.01 

1.0 

3 

18 

3.0 

Japanese  Body  II. 

CaO 

8. 

71.60 

18.71 

1.19 

— 

4.16 

0.18 

4.68 

1.0 

3 

18 

4.0 

Japanese  Body  III. 

&org. 

Subst. 

9. 

65.79 

23.51 

0.31 

1.59 

2.01 

1.73 

5.89 

1.0 

3 

15 

4.5 

Guerin  &  Co.  (Body 

CaO 

for  figures). 

10. 

69.32 

23.64 

0.83 

0.86 

2.66 

1.82 

5.98 

1.0 

3 

15 

4.5 

Guerin    &    Co.    (su- 

CaO 

perior  body). 

11. 

65.61 

23.07 

0.65 

0.80 

2.94 

2.72 

4.50 

1.0 

3 

15 

3.5 

Guerin    &    Co.)  (su- 

CaO 

perior  body). 

12. 

66.00 

22.59 

0.36 

1.68 

2.71 

1.80 

5.59 

1.0 

3 

15 

4.0 

Guerin  &  Co.  (ordin- 

CaO 

ary  body). 

13. 

64.52 

22.07 

0.97 

2.10 

1.35 

3.13 

5.60 

1.0 

3 

15 

4.0 

J.     Poyat,    Limoges 

CaO 

(ordinary  body). 

14. 

66.78 

22.70 

0.55 

0.97 

1.07 

1.51 

6.07 

0.5 

3 

15 

4.5 

Carlsbad  Body  I. 

CaO 

15. 

65.17 

23.63 

0.51 

1.09 

2.92 

0.90 

5.98 

0.5 

3 

15 

4.5 

Carlsbad  Body  II. 

CaO 

16. 

64.28 

23.49 

0.87 

1.77 

1.11 

3.07 

5.48 

1.0 

3 

15 

4.0 

J.    Poyat,    Limoges 

CaO 

(superior  body). 

17. 

66.97 

20.92 

0.64 

2.06 

2.75 

0.41 

5.43 

1.0 

3 

16 

4.0 

A.   Hache    &   Pepin 

CaO 

(superior  body). 

18. 

52.94 

28.91 

0.48 

3.99 

1.7 

0.68 

9.12 

2.0 

6 

18 

10.0 

Sevres,      Body      for 

CaO 

2.48 

table-ware. 

0.17 

C02 

MgO 

19. 

74.53 

16.09 

1.03 

0.06 

4.37 

1.19 

2.83 

1.0 

2 

15 

2.0 

Japanese  Body  I. 

CaO 

0.25 

MgO 

, 

From  a  study  of  the  foregoing  formulae  it  will  be  seen  that  there 
is  a  great  probability  of  the  hexites  or  pentites  playing  an  important 
part  in  the  structure  of  the  substances  under  consideration. 

XVI.   The  Eexite-Pentite  Theory  as  a  General  Theory  of  Chemical 

Compounds 

The  following  facts  make  it  appear  probable  that  the  new  hexite- 
pentite,  or  more  briefly  the  H.P.  theory,  which  originated  in  connection 
with  the  aluminosilicates,  is  capable  of  application  as  a  general  theory 
of  chemical  compounds. 


256  CONSEQUENCES   OF  THE   H.P.   THEORY 

A.  The  H.P.  Theory  and  the  Composition  of  the  Metal-ammonias  and  the 

Belated  Compounds 

The  H.P.  theory  appears  to  be  of  special  value  with  regard  to  the 
constitution  of  the  metal-ammonias  and  the  related  compounds.  In 
Gmelin-Kraut's  "  Handbuch  "  (1909.  V,  p.  337)  a  number  of  compounds 
termed  metal-ammonias  are  described,  and  from  the  empirical  formulae 
there  given,  the  following  may  be  selected  as  being  likely  to  contain 
hexite  or  pentite  radicles  : 

[Co(NH3)J2Cl4(PtCl6)  J  H20,  [Co(NH3)6]2(PtCl6)Cl4  •  2  H20, 
[Co(NH,).][Cr(CN).],  [Co(NH3)6][Fe(CN)6)3  [Co(NH3)6][Co(CN)6], 
[Co(NH3)5][Fe(CN)6]  -  1 J  H2O,  [Co(NH3)5][Co(CN6)], 
[Co(NH3)5N02]3[Co(N02) .]„  [Co(NH3)4NO2]S04  •  H20, 
[Co202(NH3)10](NH3)4  •  2  H20,  etc. 

Of  special  interest  are  the  compounds  : 

f   /Co2NH(NH3)8"|x 
L°\Co2NH(NH3)8JA«' 

X  =  N03,  Br,  a,  etc. 

Co4(NH3)10(N02)12  •  H20,  Co4(NH3)20(N03)10, 

Co4(NH3)10(N02)12  •  H20,  Co2(NH3)10(S04)2C03  •  4  H20. 

Also  the  compounds  : 

2  Na20  •  Co203  •  5  N203  •  H20, 

3  Na20  •  Co203  •  6  N203  •  H20, 

and  the  cobalt  oxalates  : 

Na3(NH4)3Co2(C204),  •    7  H20, 
K3Na3Co2(C204)6  •    6H20, 
K5Na19Co8(C204)24-  32  H20,  etc. 

The  hexites  clearly  play  an  important  part  in  the  following  com- 
plexes of  nitric  acid,  prepared  by  Oppenheim491  : 

K4Ni(N02)6,    K2BaNi(N02)6,    K2SrNi(N02)«,    K2CaNi(N02)6, 
K2PbNi(N02)«  and  Ba2Ni(N02),, 

from  which  it  is  impossible  to  substitute  another  metal  for  the  Ni  by 
any  of  the  ordinary  methods  of  double  decomposition. 
The  following  penta-compounds  : 

K3Cu(N02)5,  K3Zn(N02)5-6H20  and  K3Hg(N02)5  •  H20, 

also  prepared  by  Oppenheim,  are  interesting,  inasmuch  as  they  show 
that  three-fifths  of  the  OH-groups  in  pentanitrites  behave  differently 
from  the  others. 

Hexites  clearly  occur,  also,  in  the  following  compounds  prepared 
by  Soenderop492  : 

2  (K2Co2Cy12)HgJ2,  Hg3Co2Cy12  •  K6Co2Cy12,  Hg3Co2Cy12  •  Na6Co2Cylz, 
K3CoCy,,  Na3CoCy6  •  2  H20,  (NH4),Co2Cy12  •  H20, 
(NH4)6Co2Cy12  •  HgCy2  •  H20. 


METAL-AMMONIAS   AND   RELATED   COMPOUNDS     257 

The  hexites  also  play  an  important  part  in  the  yellow  and  red 
ferrocyanides,  K4Fe(CN6)  and  K3Fe(CN6)  and  in  the  double  salts 
FeCl3  •  3  KC1,  CdCl2  •  4  KC1,  etc.  * 

The  number  of  compounds  whose  composition  indicates  the  possi- 
bility of  hexites  and  pentites  playing  an  important  part  is  very  large, 
and  all  attempts  to  represent  these  atomically  have  hitherto  proved 
unsatisfactory.493  For  some  of  them,  structural  formulae  have  been 
devised,  as  Erlenmeyer's494  and  Friedel's495  formulae  for  the  ferro- 
cyanides ;  Blomstrand's496  formulae  for  ferrocyanides  and  metal- 
ammonias  ;  Jorgensen's497  formulae  for  the  metal-ammonias  and 
Remsen's498  for  the  double  salts.  Kohlschutter499  has  shown  that  the 
defects  in  all  these  suggested  formulae  are  due  to  their  limited  applic- 
ability ;  instead  of  a  broad  general  principle,  these  formulae  are  only 
related  to  special  compounds,  and  it  is  not  infrequently  found  that 
they  do  not  apply  to  apparently  closely  related  compounds. 

A.  Werner500  was  one  of  the  first  to  call  attention  to  the  repeated 
occurrence  of  the  number  6  in  inorganic  compounds  and  to  utilise  this 
in  the  formulation  of  a  theory  of  molecular  compounds  in  which  an 
attempt  was  made  to  construct  structural  formulae. 

[Werner  discovered  a  remarkable  series  of  optically  active  compounds  of  cobalt 
and  chromium,  whose  activity  he  traced,  in  this  case,  to  the  hexavalency  of  the  elements 
in  question. 

He  regarded  an  element  as  possessing,  in  addition  to  its  usual  or  "  principal  " 
valencies,  what  he  designated  "  auxiliary  "  valencies,  i.e.  a  land  of  fractional  valency 
capable  of  effecting  the  union  of  otherwise  independently  acting  molecules  like  NH3 
and  H2O.  For  the  present  purpose  it  will  be  convenient  to  distinguish  between  these 
two  types  of  valency,  though  the  manifestation  of  the  latter  is  understood  by  Werner 
to  be  independent  of  units,  being  variable  within  wide  limits  with  the  nature  of  the 
atoms  combined  and  the  external  physical  conditions.  Under  the  influence  of  both 
principal  and  auxiliary  valencies,  the  components  of  a  complex  molecular  compound 
arrange  themselves  into  zones  around  the  central  element.  The  first  zone  comprises  a 
maximum  of  four  or  six  univalent  atoms  or  groups,  this  number  going  by  the  name  of 
"  co-ordination  number,"  and  each  additional  component  of  the  complex  is  relegated 
to  the  second  zone,  where  it  takes  upon  itself  certain  peculiarities  in  behaviour,  notably 
that  of  mobility  and  consequent  tendency  to  ionisation. 

For  instance,  the  structure  of  the  well-known  complex  CoCl2  •  6  NH3  was  formerly 
written 

Cl  •  NH3  •  NH3  -  NH3  •  Co  •  NH3  •  NH3  -  NH3  •  Cl, 

a  representation  at  once  unwieldy  and  inadequate,  though  consistent  with  the  then 
prevalent  ideas  of  valency.    Werner,  however,  regards  it  as  possessing  the  structure  : 


[ 


NH3 

NH3       Co 
NH3 


in  which  the  ammonia  molecules  are  united  with  the  cobalt  atom  by  auxiliary  valencies 
and  comprise  a  first  zone  (usually  marked  by  square  brackets),  whilst  the  two  ionisable 
chlorine  atoms  fall  into  a  second.  The  six  constituents  of  the  first  zone  may  be  supposed 
to  be  arranged  symmetrically  around  the  metallic  atom,  so  as  to  be  situated  at  the  corners 
of  a  regular  octahedron  (Fig.  4),  the  position  of  the  chlorine  atoms  remaining  undefined 
by  Werner. 

Other  groups  than  NH3  may  be  included  in  the  first  zone,  in  which  case  it  is  easy 
to  see  that  isomerism  becomes  possible  with  compounds  of  the  type 


A«~l 

Me 

B*_ 


Xn 


258 


CONSEQUENCES   OF  THE   H.P.   THEORY 


This  hypothetical  tetrahedral  grouping  permits  the  prediction  of  the  possibility 
of  two  isomers,  whose  space  formulae  are  not  superposable ;  both  such  substances  should 
therefore  be  optically  active.  By  submitting  to  resolution  certain  compounds  of  the 
two  types  : 


tA  I"  A2  Co  en2  ~| 

Co  en.    I   and   I 
«w 


in  which  A  or  B  represents  Cl,  Br,  NH3,  NO2,  SCN  or  H2O  and  en=ethylene  diamine 
or  two  molecular  radicles  NH3,  Werner  obtained  isomers  with  a  very  appreciable 
rotation.  In  one  isomer  containing  a  single  atom  of  cobalt,  a  specific  rotation  of  200° 
was  obtained,  whilst  another  with  two  cobalt  atoms  gave  the  very  high  value  of  840°. 
Some  of  these  compounds  maintain  their  optical  activity  unchanged  in  solution 
for  several  months,  others  exhibit  a  phenomenon  akin  to  muta-rotation.  The  sub- 
stitution of  certain  components  of  the  complex  by  different  groups  sometimes  produces 
racemisation,  whilst  in  others  the  activity  is  preserved.  A  few  of  these  complexes  give 
a  very  considerable  rotary  dispersion.  The  peculiar  feature  about  the  chromium  com- 
pounds is  that  the  value  of  the  rotary  power  always  lies  about  150°  below  that  of  the 
corresponding  cobalt  compound,  indicating  that  the  metal  must  play  the  master-role 
in  the  production  of  the  activity.  In  his  book,  "New  Ideas  on  Inorganic  Chemistry  " 
(translated  by  Hedley),  Werner  fully  states  the  evidence  in  favour  of  his  theory  so  far 
as  it  could  be  produced  at  the  time  when  his  book  was  published.] 


NH3 


FIG.  4. 

Werner501  states  that :  "  If,  in  accordance  with  (his)  proposed 
structural  formulae,  the  elementary  atoms  forming  the  molecules  have 
their  valencies  saturated,  they  must,  nevertheless,  have  some  un- 
saturated  valencies,  as  only  in  this  way  is  it  possible  to  explain  how 
the  apparently  saturated  molecules  can  unite  with  each  other  to 
form  molecular  compounds.  It  was  formerly  the  general  belief,  and 
even  now  this  same  view  is  largely  held,  that  the  structure  of  molecular 
compounds  is  unprovable  as  they  consist  of  the  combination  of  the 
molecules  to  form  complexes  quite  apart  from  the  relationship  of  the 
atoms  concerned.  Recent  discoveries  have,  however,  shown  that  this 
combination  of  molecule  with  molecule  seldom,  if  ever,  occurs,  and 
that,  even  in  molecular  compounds,  the  combination  is  really  between 
definite  atoms.  Hence,  it  is  possible  to  devise  structural  formulae  for 
the  so-called  molecular  compounds  in  the  same  manner  as  for  the 
valency  compounds." 


WATER  OF  CRYSTALLISATION  259 

The  difference  between  the  valency  compounds  and  the  molecular 
ones  is  due,  according  to  Werner's  co-ordination  theory,  to  the  valency 
compounds  being  derived  from  compounds  in  which  the  chief  valencies 
are  saturated,  whilst  the  molecular  compounds  are  formed  by  satura- 
tion of  minor  valencies.  According  to  this  theory  the  molecular 
compounds  should  be  less  stable  than  the  valency  compounds,  yet  this 
is  by  no  means  always  the  case  :  a  very  large  number  of  the  so-called 
molecular  compounds  being  amongst  the  most  stable  substances  known ! 

The  representation  of  the  constitution  of  the  compounds  under 
consideration  by  means  of  the  H.P.  theory  overcomes  the  difficulty 
introduced  by  the  use  of  major  and  minor  valencies,  as  in  Werner's 
theory,  as  the  H.P.  theory  is  one  of  valency  compounds  and  not  of 
molecular  ones  and  is  in  full  agreement  with  the  high  stability  which 
has  been  observed. 

B.  The  H.P.  Theory  and  the  so-called  "Water  of  Crystallisation" 

The  frequent  occurrence  of  6  and  5  H2O  molecules  in  compounds 
containing  "  water  of  crystallisation  "  suggests  that  this  water  may  be 
in  the  form  of  hexites  or  pentites  and  may  thus  form  the  foundation  of 
a  theory  to  explain  the  occurrence  of  water  of  crystallisation. 

The  view  that  the  H20-molecules  can  form  hexites  and  pentites 
requires  a  higher  valency  for  oxygen  than  that  usually  ascribed  to  it. 
Various  writers  have  shown  that  oxygen  has,  at  times,  a  higher 
valency  than  2,  and  the  physical  properties  of  water  confirm  this. 
Thomsen502  has  pointed  out  that  the  water  molecules  of  salts  often 
separate  in  pairs  at  the  same  temperature,  from  which  he  concluded 
that  either  the  water  molecules  are  arranged  symmetrically  about 
the  molecule  of  the  salt  or  the  molecular  weight  of  water  is  double 
that  of  steam.  The  latter  view  requires  oxygen  to  have  a  valency 
greater  than  2. 

A  number  of  other  investigations  imply  that  water  is  capable  of 
becoming  polymerised.  Thus,  Paternos'  experiments503  suggest  that 
the  molecular  weight  of  water  in  acetic  acid  is  18  or  36,  according  to 
the  solidifying  temperature  of  the  mixture.  According  to  Eykmann504, 
water  in  paratoluidine  has  one-half,  but  in  phenol  the  full  normal 
molecular  pressure.  Walker505  has  measured  the  heat  of  liquefaction 
of  ice  in  ethereal  solution  and  concludes  that  the  molecular  weight  of 
water  is  36.  Ramsay  and  Aston506  consider  that  water  and  some  other 
substances  containing  hydroxyl,  such  as  alcohol,  acids,  etc.,  are 
molecular  aggregates  when  in  a  fluid  condition. 

[W.  R.  Bousfield  and  T.  Martin  Lowry771  have  advocated  the  view  that  liquid 
water  is  a  ternary  mixture  of  "  ice  molecules,"  "  water  molecules,"  and  "  steam 
molecules,"  these  three  varieties  being  perhaps  identical  with  Sutherland's772  "  trihy- 
drol."  Armstrong773  has  added  to  this  theory  the  conception  of  isomeric  molecules, 
of  equal  size,  but  different  structure.  Moreover,  Tamman774  has  prepared  at  least 
four  polymeric  forms  of  ice  : 


dihydrone"          V)  =  OC          with 
H/          XH 


260  CONSEQUENCES  OF  THE   H.P.   THEORY 

H\      /OH 

"  hydronol "          >O< 

H/     XH 

and  BO  forth.  Such  extensions  as  these  have  been  found  to  be  necessary,  in  order  to 
explain  the  experimental  data  that  have  been  accumulated  in  recent  years,  and  must 
now  be  regarded  as  essential  parts  of  the  theory  of  the  constitution  of  water. 

Even  steam,  so  long  considered  as  a  uniform  material  that  could  be  represented 
accurately  by  the  much-beloved  and  greatly  over- worked  formula  H2O,  has  been  shown 
by  the  careful  measurements  of  Bose776  to  be  a  mixture  of  simple  and  polymerised 
molecules,  e.g. 

H4O2  2  H2O 

the  proportion  of  the  substance  in  the  simpler  form  being  reckoned  at  91  per  cent,  in 
the  neighbourhood  of  the  boiling  point.] 

Kohlrausch  and  Heydweiller507  and  H.  Ley508  have  found  that  the 
electrolytic  dissociation  of  water  is  greatly  increased  on  raising  the 
temperature.  The  "  acidity,"  which  is  very  feeble  at  the  ordinary 
temperature,  increases  to  such  an  extent  that  at  100°  C.  it  is  almost 
equal  in  strength  to  that  of  phenol.  This509  is  clearly  shown  in  the 
following  Table,  in  which  t  is  the  temperature,  d  the  degree  of  dissocia- 
tion and  K  the  affinity  coefficient : 

t  d                                K 

0°  0.35  •  10-7  0.12  •  10-14 

10°  0.56  •  10-7  0.31  •  10-14 

18°  0.80  •  10-7  0.64  •  10-14 

34°  1.47  - 10-7  2.20  •  10"14 

50°  2.48  •  10-7  6.20  •  10~14 

The  strength  (K)  of  the  water  increases  considerably  in  the  interval 
between  0°  and  50°,  and  at  100°  has  a  value  at  least  a  thousand  times  that 
at  zero.  This  enormous  increase  in  the  strength  at  higher  temperatures 
is  explicable  on  the  assumption  that  polymerisation  occurs  in  the  sense 
of  the  H.P.  theory. 

Assuming  that  oxygen  has  a  higher  valency  than  2  and  that 
water  can  form  polymerisation  products,  the  constitution  of  water- 
hexite  and  water-pentite  may  be  represented  graphically  by  : 


\/ 

6  H20  5  H20 

which  may  be  abbreviated  to  H  or  H  or  to  A  and  -. 

Such  compounds  may  then  be  represented  in  more  complex  ones  as 
follows  : 

ii     T     ii 

2  Si  |  Al  |  Si  C 

I1      i      I1 
9  H20  •  3  A1203  •  12  Si02  •  4  H  •  2  H. 


WATER  OF  CRYSTALLISATION  261 

The  bonds  between  the  rings  in  this  aluminosilicate  are  loosened  by 
the  manner  in  which  the  cyclic  water  (or  water  of  crystallisation)  is 
attached,  and  the  position  and  mode  of  attachment  of  the  water  of 
crystallisation  weakens  or  destroys  the  bonds  between  the  base  and 
the  remainder  of  the  molecule. 


The  Theory  and  the  Facts 
I.    Hydro-aluminosilicates 

The  structural  formulae  shown  below  may  be  derived  from  the 
hydro-aluminosilicates  given  on  page  105. 


I      II      I 
_/\/\/\_ 


Ill  I      i       I 

\/\/\_,  ,__  /\/\/\_, 

All  Si  |  All  |Al|Si|Al|         or        A1  Si   Al 

•--\/\/\/—  '  —  \/\/\/~'          ~\/\ 

I      II      I  I      II      I  I      II 

H?2(A1  •  SAi  •  Al)  •  4  H  •  H  H?2  (Al  •  Si  •  Al)  •  4  H  -  2  H 


I  Al  Si   Al|          or 

XV  J > 

HJ,(A1  •  Si  •  Ai)  •  6  H 


I      II       I  I       II      I 

.x\/\/\_,        _/\/\/\. 

|A1  Si   All          or        I  All  Si   All 


II  J_  |_ 

H°10(Al-Sl- Al)  -4H-H. 

The  position  of  the  various  water-rings  implies  (in  agreement 
with  theory)  that  these  aluminosilicates  are  readily  decomposed  by 
acids.510  A  further  study  of  these  compounds  must  show  that  the 
easily  separable  water  —  the  cyclic  water  —  must  be  attached  with 
varying  degrees  of  strength. 

II.   Hydro-ferrosulphates 

0.  Kuntze511  has  studied  the  loss  of  water  undergone  by  a  mineral 
of  the  composition 

6  Fe,03  •  18  SO,  •  62  H,0 


CONSEQUENCES  OF  THE   H.P.   THEORY 

at  different  temperatures.    If  the  results  obtained  by  him  are  calculated 
into  formulae,  they  agree  surprisingly  well  with  the  structural  formula  : 


Fe 

_  l 

as  may  be  seen  from  the  following  figures  : 


Calcd. 

Found 

40H20 

20.48% 

21.  04%  split  off  at  105°  C. 

8H20 

4.07% 

fr.UO  /o           },                ,, 

110° 

2H20 

1.030/0 

0.790/0           „                „ 

130° 

8H20 

4.090/0 

4,060/0      „         „ 

140° 

4H20 

2.050/0 

2.38%      ,,         ,, 

red  heat 

6  Fe203 

27.30% 

26.86% 

18  SO, 

40.950/0 

39.01% 

A1203  0.27% 

Insoluble  1.79. 

This  shows  that  the  water  pentites  are  split  off  at  105°,  the  weakly 
bound  "water  of  constitution"  of  the  S03  side-chains  at  110°,  the 
more  strongly  bound  "  water  of  constitution  "  of  the  middle  S03-ring 
at  130°,  the  remainder  of  the  "  water  of  constitution  "  of  the  S03  side- 
chains  at  140°,  and  the  "  water  of  constitution  "  of  the  iron-ring  and 
the  remainder  of  the  water  of  the  middle  S03-ring  at  red  heat. 

III.  The  Water  of  Crystallisation  in  the  Alums 

In  the  light  of  the  above  theory  of  water  of  crystallisation,  the 
alums  possess  the  following  structural  formula  : 


iiii 
3  K20  •  12  H2O  •  3  R208  •  12  S03  •  10  H. 

From  this  structural  formula  it  follows  that : 

1.  Five-sixths  of  the  water  (the  hexite  water)  must  be  bound  more 
loosely  than  the  rest. 

2.  The  bond  between  the  rings  on  the  one  part,  and  between  the 
rings  and  the  base  on  the  other,  must  increase  with  the  amount  of 
water  split  off. 

These  consequences  of  the  theory  agree  with  the  facts,  as  Van 
Cleef 512  has  shown  that  the  gradual  and  steady  loss  of  water  molecules 
which  occurs  in  the  alums  when  the  heating  is  continued  after  five- 
sixths  of  the  total  water  have  been  removed,  is  very  noticeable. 
Recoura513  and  Whitney514  have  found  that  on  heating  chrome-alum 


WATER   OF   CRYSTALLISATION   IN   ALUMS  263 

at  1 10°  to  constant  weight,  a  new  alum  with  new  properties  is  obtained. 
This  new  compound  is  readily  soluble  in  water,  but,  unlike  the  true 
alums,  is  not  precipitated  by  barium  chloride,  i.e.  the  new  compounds 
contain  no  S04-ions  ;  the  bond  between  the  S03  and  Cr2O3  is  strength- 
ened by  the  loss  of  H. 

Water-free  chrome  alum  may  clearly  occur  in  two  isomeric  forms 
as  shown  in  the  following  structural  formulae  : 

I  til 


S    Cr 


|s|" 
\/~~ 


A. 

Ortho  compound. 

It  is  interesting  to  note  that  the  free  acids  of  this  chrome  alum 
have  been  prepared  by  both  Recoura  and  Whitney. 

A  glance  at  the  structural  formulae  of  the  compounds  A  and  B 
shows  that  these  substances  behave  very  differently  in  both  chemical 
and  physical  properties.  The  basic  or  H-atoms  in  the  ortho-compound 
are  more  easily  separated  than  those  in  the  para-compound.  As  a 
matter  of  fact,  the  ortho-compound  (the  green  modification)  has  a 
measurable  electrical  conductivity,  whilst  the  yellowish  brown  or  para- 
compound  shows  no  such  conductivity. 

The  lowering  of  the  freezing  point  of  the  green  acid  (A  compound) 
is  0.24°,  that  of  the  yellowish  brown  or  B  compound  is  0.07°.  Accord- 
ing to  Whitney  the  green  modification  can  be  converted  into  the 
yellowish  brown  one  which,  in  aqueous  solution,  has  the  appearance 
of  absinthe.  It  gelatinises  after  a  few  days. 

IV.  The  Water  of  Crystallisation  of  Chromo  -Sulphuric  Acids 

According  to  the  new  theory  of  water  of  crystallisation  enunciated 
above,  the  two  chromo-sulphuric  acids  studied  by  Recoura,*  namely  : 
12  H20  •  6  Cr203  •  18  SO3  •  96  H20  (violet  chromo-sulphuric  acid)  and 
12  H20  •  6  Cr2O3  •  18  S03  •  36  H2O  (green  chromo-sulphuric  acid) 
must  have  the  following  structural  formulae  : 

fl       1       V      I        fl  II       j       jl       j       )l 

<=/\/\/\/\/\—>  ==/\/\/\/\/\== 

<=|  S  |  Cr  |  S  |  Cr    S  ~>  J  S  |  Cr  |  S  |  Cr  |  S  |= 

VVVVV  VYxii  xj  j 

Violet  Chromo-sulphuric  acid.  Green  Chromo-sulphuric  acid. 

A.  B. 

*  When  chromic  hydrate  is  dissolved  in  sulphuric  acid  the  solution  is  at  first  green, 
but  after  a  while  changes  to  violet  and  deposits  violet-blue,  regular  octohedra  to  which 
is  ordinarily  assigned  the  formula  Cr2(SO4)315  H2O,  the  proportion  of  water  being  some- 
what uncertain.  In  the  corresponding  salts,  the  green  variety  gradually  changes  to 
violet  at  ordinary  temperatures  when  in  solution,  but  on  boiling  the  violet  changes 
rapidly  into  the  green  variety.  It  is  generally  stated  that  the  green  variety  does  not 
crystallise,  and  there  is  good  reason  to  suppose  that  it  is  colloidal.  —  A.  B.  S. 


264  CONSEQUENCES   OF  THE   H.P.   THEORY 

I      ii 


or 


A  glance  at  the  structural  formulae  of  the  compounds  A,  B  and  C 
will  show  that  the  A  compound  must  be  less  stable  than  B  and  C  as  it 
contains  more  water  hexites.  The  Cr  and  S  rings  of  the  B  and  C 
compounds  must  be  more  strongly  bound  than  those  in  compound  A . 

This  consequence  of  the  theory  is  confirmed  by  the  discovery  of 
Recoura,  that  the  addition  of  barium  chloride  to  the  violet  solution 
produces  an  immediate  precipitate,  whilst  the  green  solution,  when 
similarly  treated,  undergoes  no  apparent  change. 

The  theory  also  explains  the  following  behaviour  of  the  green  acid  : 
In  the  air  it  appears  to  remain  unchanged  for  several  years,  but  its 
aqueous  solution  is  very  unstable  and.  on  the  addition  of  barium 
chloride,  only  a  weak  precipitate  forms  even  after  an  hour.  In  time,  a 
more  labile  bond  is  formed  between  the  rings  of  the  acid  by  the 
addition  of  water  hexites. 

If  the  nature  of  the  separation  of  the  water  hexites  in  the  A 
compound  is  compared  with  that  of  the  ferrosulphuric  acid,  a  definite 
analogy  is  observed.  Here,  also,  the  water  hexites  in  the  chrome  and 
middle  S03-rings  are  more  firmly  bound  than  the  water  hexites  in  the 
side  S03-rings. 

On  heating  to  90°,  or  more  rapidly  when  boiled,  the  violet  acid,  or 
A  compound,  forms  a  green  solution  the  composition  of  which,  as 
Recoura's  experiments  have  shown,  has  nothing  in  common  with  the 
solid  green  acid. 

The  fact  that  the  colour  of  a  compound  can  be  changed  by  the 
addition  of  water  to  its  molecule,  closely  agrees  with  the  view  that  a 
change  of  colour  may  occur  in  a  dilute  aqueous  solution  on  account  of 
the  combination  of  water  hexites  or  pentites. 

Recoura  has  studied  the  chemical  reactions  of  the  solution  in  a 
thermo-chemical  manner.  If  increasing  amounts  of  sodium  are  added 
to  the  green  solution,  the  heat  evolved  on  the  addition  of  an  amount 
of  sodium  equivalent  to  one-sixth  of  the  sulphuric  acid  of  the  sulphate 
will  be  equal  to  the  heat  evolved  when  sodium  combines  with  an  acid, 
whereas  all  other  proportions  of  sodium  evolve  much  less  heat. 

From  this  it  follows  that  on  boiling  a  compound  of  the  type 

S  •  Cr  •  S  •  Cr  •  S  it  is  converted  into  the  penta-compound  S  •  Cr  •  S  • 
Cr  •  S  with  resulting  separation  of  three  molecules  of  sulphuric  acid.  On 
treating  the  green  sulphate  S  •  Cr  -  S  •  Cr  •  S  with  BaCl2  a  very  stable 

compound  of  the  type  S  •  Cr  •  Cr  •  S  is  formed,  as  already  noticed  in 
connection  with  other  complexes,  and  according  to  Recoura  only  one- 
fifth  of  the  penta-acid  is  precipitated. 


WATER   OF  CRYSTALLISATION   IN   ACIDS  265 

If  the  mixture  of  green  penta-acid  is  allowed  to  stand  a  long  time, 
the  penta-  is  converted  into  the  violet  hexa-acid.  The  penta-acid  has 
not  yet  been  prepared. 

Whitney  has  tested  Recoura's  results  by  modern  physio -chemical 
methods  and  has  fully  confirmed  them. 

Attention  may  also  be  directed,  in  this  connection,  to  the  hydrates 
of  the  cerium,  praesodymium  and  neodymium  sulphates  studied 
by  Roelig515.  For  instance,  a  concentrated  solution  of  cerium  sulphate 
at  25°  forms  the  duodecihydrate  Ce2(SO4)3  12  H2O  ;  between  30°  and 
40°  C.  the  octohydrate  Ce2(S04)3  8  H20,  and  at  temperatures  above  74° 
the  pentahydrate  Ce2(S04)3  5  H2O. 

The  structural  formulae  of  these  acids,  according  to  the  H.P. 
theory,  are  : 

fi     i     ii     i     ii  it     i     it     i     ii  ii      i     ii     i     ii 

"III  SjOe|  SJCeJ  S  |^  l!|  S  |Ce|  S  J  OeJ  S  jjl  I]  S]Ce[SjCeJ  SjII 


I1        I        IJ        I        I]  H        I        II        I        II  II        I        II        I        II 

"Duodecihydrate."  "Octohydrate."  "Pentahydrate." 

That  the  bond  between  the  rings  and  the  base  is  weakened  by  the 
addition  of  water  radicles — hexite  and  pentite — is  shown  by  the 
following  facts  : 

1.  According  to  an  article  in  the  "Papierzeitung"516,  two-thirds 
of  the  acid  in  a  saturated  solution  of  aluminosulphuric  acid  (366  g. 
aluminium  sulphate  per  litre)  may  be  neutralised  with  trinomial 
caustic  soda  solution,  a  permanent  precipitate  being  formed.  If  the 
original  solution  is  diluted  ten  times,  only  as  much  base  is  taken  up  as 
will  correspond  to  one- third  of  the  sulphuric  acid. 

From  this  it  follows  that  in  a  concentrated  solution  all  the  H-atoms 
of  the  acid  may  be  replaced  by  a  base,  but  in  a  dilute  solution  only 
half  of  these  atoms  can  be  so  replaced. 

The  structural  formula  of  the  aluminosulphuric  acid  under  con- 
sideration is  : 

-AAAAA= 


"|  8  I  All  S  |  All  S  |~~  •*<! 

— \/\A/\/\/~~ 

H    i    it    i    H 


In  a  concentrated  solution,  24  OH-groups  are  replaced  by  OR',  but 
only  12  hydroxyls  are  replaced  in  a  dilute  solution. 

2.  Gittelson517  has  found  that  by  treating  concentrated  cerium 
solutions  with  concentrated  phosphate  solutions,  salts  are  produced 
such  as 

3  Na20  -  6  Ce208  -  6  Pa05  •  24  HaO, 

but  with  dilute  solutions  of  these  substances  free  acids  are  produced. 


266  CONSEQUENCES  OF  THE   H.P.   THEORY 

C.     The  H.P.  Theory  and  the  Dissociation  Theory  of  Arrhenius 

It  has  been  shown  in  the  foregoing  pages  that  the  addition  of 
cyclic  water  affects  the  bond  of  the  rings  and  the  ions.  On  the  addition 
of  water  of  crystallisation  the  bond  between  the  rings  is  reduced  and  the 
ionisation  increased.  This  fact  is  of  great  value  in  formulating  a  new 
theory  of  solutions.  It  leads  to  the  "  Dissociation  Theory  "  of  Ar- 
rhenius and  gives  it  a  new  experimental  basis. 

According  to  Nernst518,  it  is  always  questionable  whether  a  mole- 
cule in  solution  adds  water  molecules  or  not,  as  the  Raoult  and  van't 
Hoff  methods  give  no  definite  results  in  this  respect.  Yet  in  view  of  the 
strong  disdynamic  action  of  water  there  can  be  no  doubt  that  the 
dissociation  of  a  solution  of  a  salt  on  increasing  dilution  is  accompanied 
by  the  addition  of  water. 

Hence  the  fundamental  law  of  van't  Hoff  in  regard  to  solutions — 
viz.  that  in  highly  dilute  solutions  substances  assume  a  condition 
similar  to  gases519 — appears  in  a  new  light.  Van't  Hoff  first  suggested 
that  the  osmotic  pressure  of  a  solution  (e.g.  sugar  in  water)  is  as  great 
as  the  pressure  produced  by  an  equal  quantity  of  the  dissolved  sub- 
stance if  the  latter  were  in  the  form  of  a  gas  occupying  the  same 
space  as  the  solution.  Yet  no  one  had  ever  explained  why  dissolved 
substances  should  behave  in  this  manner  and  no  reason  was  known  as 
to  how  the  osmotic  pressure  was  created.  The  authors'  view  (that 
an  addition  of  water  molecules  to  the  molecules  of  the  substance  in 
solution  occurs)  indicates  the  existence  of  a  definite  attractive  force 
between  the  molecules  dissociated  by  the  water  and  the  water  outside 
the  semi-permeable  membrane,  and  that  that  attractive  force  is  the 
cause  of  the  osmotic  pressure. 

Numerous  other  facts  may  be  equally  easily  explained  in  the  light 
of  this  new  theory  ;  amongst  others  are  the  formation  of  hydrates  in 
solutions,520  the  presence  of  molecular  aggregates  in  concentrated 
solutions  and  their  destruction  on  dilution,  e.g.  the  dissociation  of  the 
ether  molecular  aggregate  (CH3  •  O  •  CH3)  n,  the  aggregate  CH3  •  CO  • 
NH2  in  aqueous  solution  and  several  thermo-chemical  phenomena. 

The  view  that  hydrates  are  formed  in  aqueous  solutions  is  held  by 
a  number  of  authorities,  some  of  whom  have  supported  their  opinion 
by  experimental  evidence,  as  :  A.  Werner521,  Abegg  and  Bodlander522, 
Euler523,  Hantzsch524,  Lowry525,  Tournier  d'Albe526,  Jones  and  his 
associates527,  V.  Kohlschiitter528,  Vaillant529,  R.  J.  Caldwell530,  H.  E. 
Armstrong  and  J.  A.  Watson531,  E.  H.  Renni,  A.  J.  Higgin  and  W.  F. 
Cooke532  and  others. 

A.  Werner533,  as  early  as  1893,  expressed  his  opinion  that  electro- 
lytic dissociation  is  necessarily  accompanied  by  the  formation  of  a 
compound  with  the  solvent  used.  "According  to  the  results  shown 
by  our  experiments,"  says  Werner,  "  the  existence  of  hydrates  in 
aqueous  solution  is  not  merely  an  inference  from  the  hydrate  theory  ; 
these  hydrates  form  an  essential  condition  of  electrolytic  dissociation. 


THE   DISSOCIATION   THEORY   OF  ARRHENIUS        267 

In  an  aqueous  solution  the  ions  are  not  metallic  atoms,  but 
metallic  atoms  combined  with  six  water  molecules,  the  whole  forming 
definite  radicles.  This  shows  clearly  why  the  electrical  conductivity 
and  the  dissociation  of  a  salt  are  so  closely  related  to  the  solvent." 

Abegg  and  Bodlander  suggested  that  a  hydration  of  the  anions  and 
cathions  occurs.  The  degree  of  hydration  of  the  alkali-ions  increases  in 
the  following  order  :  K,  Na,  Li,  etc.  Feebly  dissociating  solvents  are 
those  with  feeble  affinity  for  ions,  and  vice  versa. 

Euler  also  adopted  the  idea  of  a  hydration  of  ions  taking  place  in 
aqueous  solutions,  and  attributed  to  nickel,  copper  and  cobalt  ions 
the  formulae  : 

[Ni(H20)4]++,  [Cu(H20)4]++and  [Co(H20)6]++. 

An  acid  in  aqueous  solution  is,  according  to  Hantzsch,  a  "  hydronium- 
salt."  The  ions  of  hydrochloric  acid  in  aqueous  solution  are,  according 
to  him  : 

HC1  +  H20  =  [H20,  H]C1  =  (H30)+  +  C1-. 

This  reaction  is  analogous  to  the  formation  of  an  ammonium  salt  from 
an  acid  and  ammonia  : 

HC1  +  NH3  =  NH3  •  HQ  =  (NH4)+  +  C1-. 

Lowry  also  regards  the  nature  of  electrolytic  dissociation  from 
the  point  of  view  of  a  hydration  theory. 

Tournier  d'Albe  touched  upon  the  problem  of  hydrated  ions  in  his 
work  on  the  theory  of  electrons  and  expressed  the  opinion  that  each 
molecule  draws  molecules  of  the  solvent  to  itself  and  becomes  hydrated. 

According  to  the  most  recent  results  published  by  Jones  and  his 
associates,  the  lowering  of  the  freezing  point  of  concentrated  solutions 
shows,  beyond  a  doubt,  that  hydrates  exist  in  solution.  Vaillant  has 
definitely  discovered  the  existence  of  hydrates  in  aqueous  solution  by 
means  of  spectrometric  investigations. 

R.  J.  Caldwell  has  shown  that  the  speed  of  inversion  of  raw  sugar 
by  hydrochloric  acid  may  be  increased  by  the  presence  of  various 
chlorides.  To  explain  this  phenomenon  Caldwell  supposes  the  salt  to 
be  hydrated  in  solution,  a  portion  of  the  water  thereby  losing  some 
of  its  solvent  power,  and  thus  effects  a  "  concentrated  "  action  on  the 
sugar.  To  determine  the  "  average  hydration  "  of  a  given  salt  it  is  only 
necessary  to  ascertain  experimentally  how  much  water  may  be  added 
to  the  salt  solution  in  order  to  reduce  the  speed  of  reaction  to  its 
original  amount. 

H.  E.  Armstrong  and  J.  A.  Watson  investigated  the  action  of  salts 
on  the  speed  of  hydrolysis  of  methyl  acetate  by  nitric  and  hydrochloric 
acids.  They  found  that  in  most  cases  the  presence  of  a  salt  increased 
the  speed  and  attributed  this  to  the  hydration  of  the  salt. 

E.  H.  Rennie,  A.  J.  Higgin  and  F.  W.  Cooke  examined  the  effect  of 
various  nitrates  on  the  speed  of  solution  of  copper  in  nitric  acid,  and 
found  that  the  presence  of  sodium  nitrate,  and  particularly  lithium 


268  CONSEQUENCES   OF  THE   H.P.   THEORY 

nitrate,  caused  a  considerable  increase  in  the  rate  of  solution.  Potas- 
sium nitrate  was  without  effect  and  calcium  nitrate  and  rubidium 
nitrate  diminished  the  rate  of  solution.  Beginning  with  the  nitrate 
possessing  the  greatest  accelerative  power  the  salts  may  be  arranged 
thus  :  Li,  Na,  K,  Rb,  Cs,  which  is  the  same  order  as  Wymper  found  for 
their  action  on  the  speed  of  inversion  of  cane  sugar,  and  these  authors 
attributed  it  to  the  same  cause,  viz.  the  "  concentrated  action  "  which 
these  salts  possess  on  account  of  their  hydration.  The  same  authorities 
also  conclude  that  the  investigations  mentioned  form  a  further  proof  of 
the  combination  of  the  solvent  with  the  dissolved  substance. 

The  experimental  investigations  of  a  number  of  other  authorities 
and  the  opinions  expressed  by  them  all  point  to  the  necessity  of  a 
complete  agreement  between  any  theory  of  "  water  of  crystallisation  " 
and  any  theory  of  "  solution." 

D.    The  H.P.  Theory  and  the  Constitution  of  Simple  Acids 

As  the  complex  acids  may  be  formed  from  simple  ones,  it  must  also 
be  possible  to  form  cyclic  compounds  including  those  in  which  an  acid 
is  not  combined  with  other  acids.  A  number  of  facts  in  support  of 
this  application  of  the  new  theory  of  the  simple  acids  may  be  men- 
tioned : 

1.  Tammann534  prepared  the  following  salts  of  a  hexa-phosphoric 
acid  : 

K2Ag4(P03)cH20, 

K4Ag2(P03)6, 

K2Na4(P03)6, 

K4Na2(P03)6, 

3[K2Sr2(P03)6]4H20, 

Li2(NH4)4(P03),8H20, 

Li2H4(P03)64H20, 

Li2Na4(P03)66H20. 

And  the  following  from  a  penta-phosphoric  acid  : 

(NH4)K4(P03)5*6H20, 

(NH4)Na4(P03)5, 
(NH4)Li4(P03)5, 

(NH4)K4(P03), 

The  following  compounds,  also  prepared  by  Tammann,  are  also  of 
interest,  and  are  clearly  related  to  a  di-,  penta-,  hexa-phosphoric  acid  : 

Mg,Na4(PO,)18, 
Ca6Na4(P03)16, 
Mn6Na4(P03)i,. 

From  the  theory  of  the  constitution  of  complex  acids  formulated 
by  the  authors  of  the  present  volume,  it  follows  that  the  hydroxyls  of 
the  hexa-  or  penta-radicles  are  partly  acido-  and  partly  baso-philic, 
i.e.  the  water  they  contain  is  not  all  bound  to  the  radicles  with  the  same 


THE   CONSTITUTION   OF  SIMPLE   ACIDS  269 

degree  of  force.   This  consequence  of  the  theory  also  follows  from  the 
physio-chemical  investigations  of  the  above  acids  by  Tammann. 
In  the  compounds 

(a)  K2Na4(P03)., 
and 

(b)  Na2Na4(P03)«, 

a  positive  current  only  removes  one-third  of  the  base. 

By  the  prolonged  action  of  AgN03  on  K6(P03)6,  Tammann  was 
able  to  replace  two-thirds  of  the  base  by  Ag. 

The  behaviour  of  the  compound  (NH4)5  (P03)5  towards  sodium  and 
potassium  shows  that  one-fifth  of  the  base  in  it  behaves  differently 
from  the  remainder.  The  same  is  shown  by  the  molecular  conduc- 
tivity of  this  ammonium  salt  and  the  conductivity  of  other  salts 
obtained  from  it,  such  as  : 

(NH4)(NH4)4(P03)6, 

(NH4)Na4(P08)6, 

(NH4)Li4(PO,)6. 

If  the  absolute  speeds  of  the  ions  are  calculated  by  Kohlrausch's 
method  (by  the  addition  of  the  maximum  values)  the  following  maxima 
are  obtained  : 

(NH4)(NH4)4(P03)6        (NH4)Na4(P08)8        (NH4)Li4(POs)5 
A.  oo  =  300  A  co  =  230  A  co  =  210 

The  maximum  values  actually  found  are  for  the  ammonium  salt  125, 
for  the  ammonium-sodium  salt  96,  and  for  the  ammonium-lithium 
salt  90. 

These  figures  can  be  most  easily  understood  by  assuming  that 
one-fifth  of  the  base  passes  away  in  the  form  of  cathions  whilst  the 
remainder,  with  the  acid,  has  the  function  of  anions. 

2.  The  hexitic  structure  of  phosphoric  acid  in  simple  salts  is 
shown  in  the  following  compounds,  prepared  by  Gluhmann535 : 

2  BaO  •  3  Na20  •  3  P205  •  11  H20, 
2  CaO  •  3  Na20  •  3  P205  •  6  H2O, 
2  CuO  •  3  Na20  •  3  P205  •  12  H20, 
2  FeO  •  3  Na20  •  3  P205  •  12  H20, 
2  MnO  •  3  Na2O  •  3  P2O5  •  12  H2O, 
2  NiO  •  3  Na2O  •  3  P2O5  •  24  H20, 
2  CoO  •  3  Na20  •  3  P2O5  •  24  H2O, 
2  MgO  •  3  Na2O  •  3  P2O5  •  12  H20. 

In  these  compounds  two-fifths  of  the  OH-groups  clearly  behave  in 
a  manner  different  from  the  rest.  Analogous  compounds  of  niobic  and 
tantalic  acid  with  a  small  proportion  of  base  have  been  obtained  by 
Marignac536 : 

4  H20  •  4  K2O    •  3  Nb205  •  12  H20, 

Na20-3K20    -3Nb205*    9  H20, 

K2O   -3Nb205-    5H20, 

4  K20    •  3  Ta205  •  16  H20, 


270  CONSEQUENCES  OF  THE   H.P.   THEORY 


4 

Na2O 

•3Ta 

205  •  24 

H20, 

4 

Ag20 

•3 

Ta 

205  • 

3 

H 

A 

4 

BaO 

•3 

Ta 

205  - 

6 

H 

.0, 

4 

MgO 

•3 

Ta 

205  • 

9 

H 

.0, 

4 

HgO 

•3 

Ta 

205  • 

5 

H 

,0. 

3.  The   composition   of   the   following   compounds   prepared   by 
Hallopeau537  shows  the  presence  of  hexites  and  pentites  in  some  simple 
salts  : 

5  K20  •  5  (NH4)20  •  24  W03  •  22  H20, 

3  (NH4)20  •  3  Na2O  •  16  W03  •  22  H20, 

4  (NH4)20  •  Na20  •  12  W03  •  14  H2O, 

2  Na20  •  3  (NH4)2O  •  12  W03  •  15  H20, 

3  (NH4)20  •  3  Na20  •  12  W03  •  22  H20, 

5K20   -^WO.-llH.O, 
Na20  •  10  W03  •  21  H20,  etc. 

4.  A  number  of  oxygen-free  salts  have  properties  confirmatory  of 
a  hexitic  or  pentitic  structure.     Thus,  the  formulae  CsCl4I,  RbClJ, 
KC14I,  LiCl4I,  etc.,  indicate  the  presence  of  pentite  compounds.    The 
formulae  KI3,  CsBr3,  CsClBr2,  RbCl2I,  etc.,  should  probably  be  doubled 
and  are  then  characteristic  of  hexites.      Bredig538  has  discovered  that 
in  the  compound  KI3  or,  more  correctly,  K2I6  the  group  I6  behaves 
like  an  independent  ion,  and  is  reminiscent  of  Tammann's  investiga- 
tions on  the  hexa-  and  penta-acids. 

It  is  thus  possible  that  free  halogen  acids,  H2X6(X=C1,  Br,  I), 
may  exist.  The  great  solubility  of  chlorine  in  highly  concentrated 
solutions  of  HC1  led  Berthelot539  to  the  conclusion  that,  under  such 
conditions,  the  compound  HC13  or  H2C16  is  formed  in  a  manner 
analogous  to  the  production  of  K2I6  by  the  solution  of  iodine  in 
potassium  oxide.  That  a  chemical  compound  is  formed  in  this  manner 
has  been  conclusively  shown  by  the  work  of  Le  Blanc  and  Noyes. 

£.    The  H.P.  Theory  and  the  Carbon  Compounds 

It  may  appear  to  be  somewhat  late  to  attempt  to  apply  the  H.P. 
theory  to  the  carbon  compounds  in  general,  although  the  classical 
researches  of  Berzelius,  Liebig,  Kolbe  and  others540  were  made  by 
men  who  sought  for  laws  applicable  to  organic  chemistry  in  those 
which  applied  to  inorganic  compounds.  Nevertheless,  a  few  facts 
may  be  pointed  out  which  indicate  that  such  an  application  of  the 
H.P.  theory  is  not  without  value. 

Just  as  the  aluminosilicates  are  converted  into  kaolin  and  may  be 
produced  from  kaolin,  so  may  the  carbon  compounds  be  converted 
into  carbonic  acid  or  may  be  formed  from  it.  For  instance,  it  is  well 
known  that  plants  take  carbonic  acid  from  the  air  and  convert  it  into 
oxalic  acid  and  the  various  kinds  of  sugar  ;  from  these  the  animal 
fats  and  other  complex  organic  compounds  are  formed.  Oxalic  acid 
is  also  a  common  product  of  the  oxidation  of  both  simple  and  complex 


CARBON   COMPOUNDS  271 

organic  bodies.  Thus,  it  is  produced  in  varying  amounts  by  suitably 
treating  various  carbo-hydrates,  fatty  acids,  oils  and  glycerin :  all  the 
complex  carbon  compounds  which  can  be  oxidised  by  nitric  acid. 

Oxalic  acid,  like  all  inorganic  acids,  forms,  according  to  Rosen- 
heim541,  complex  acids  with  other  inorganic  acids,  hexites  or  pen- 
tites  being  produced  under  suitable  conditions.  A  hexitic  structure 
of  oxalic  acid  is  also  found  in  a  series  of  other  compounds  as  in  the 
cobalt  oxalates  mentioned  on  p.  256. 

It  is  also  important  to  note  that  carbonic  acid  can  also  form 
complexes  with  phosphoric  acid,  these  complexes  playing  a  large  part 
in  the  formation  of  the  bony  framework  of  the  animal  organisms. 
According  to  Hoppe-Seyler  (vide  Scheffs  "Handbuch  d.  Zahnheilk." 
1909,  1,  362)  the  compound  10  CaO  •  C02  •  3  P2O  is  contained  in  the 
dentine  and  enamel  of  natural  teeth.  To  this  basic  carbo-phosphoric 
calcium  salt  the  following  structural  formula  may  be  assigned  : 

Ca3  Ca3 


P 

v         , 

II 

Ca3 


NX 

Ca3 


Thus,  the  chief  constituent  of  dentine  and  of  natural  dental  enamel 
has  a  chemical  constitution  similar  to  the  ^-complexes  (p.  76),  which 
are,  as  a  rule,  more  stable  than  the  a-complexes.  This  view  of  the 
structure  of  dentine  and  enamel  makes  it  easier  to  understand  the  far 
higher  resistance  of  the  latter  to  acids  than  is  possessed  by  calcium 
phosphate,  and  explains  the  strong  combination  of  the  carbonic  acid 
and  lime  in  the  dentine.  Without  some  such  structural  formula  these 
properties  are  extremely  puzzling. 

When  these  facts,  together  with  the  figure  6  for  the  carbon 
atoms  in  the  general  formulae  for  the  sugars  n(C6H12O6) — (n-  1)H2O 
and  the  genetic  relationship  between  oxalic  acid  and  the  sugars  are 
considered,  the  thought  naturally  arises  that  the  transformation  of 
oxalic  acid  into  sugar  by  plants  may  possibly  be  due  to  both  oxalic  acid 
and  the  sugars  possessing  cyclic  structures.  In  an  analogous  manner 
it  is  possible  to  explain  the  constitution  of  the  sugar-like  product 
obtained  by  Buttlerow542  from  formaldehyde  and  calcium  hydroxide. 
This,  according  to  Loew543,  is  a  single  compound  with  the  formula 
C6H12O6 ;  E.  Fischer  and  F.  Passmore544  regard  it  as  a  mixture  of 
various  aldehydic  or  ketonic  alcohols  from  which  a-acrose  may,  in 
all  cases,  be  separated.  This  a-acrose  is,  according  to  E.  Fischer, 
closely  related  to  the  natural  sugars. 

A  possible  value  of  the  H.P.  theory  may  lie  in  its  application  to 
the  formation  of  sugars  from  carbonic  acid,  as  the  assimilation  of 
carbonic  acid  by  plants  is  the  chief  reason  for  their  existence  as  living 
organisms.  The  smallest  observation  which  will  assist  in  revealing  the 


272  CONSEQUENCES   OF  THE   H.P.   THEORY 

secret  methods  by  which  plants  effect  this  transformation  is  therefore 
of  great  importance. 

Even  if  the  existence  of  a  large  number  of  hexites  and  pentites  in 
some  carbon  compounds  may  be  considered  doubtful,  yet  their  presence 
in  certain  carbon  compounds  is  highly  probable.  The  latter,  which  are 
termed  aromatic  compounds,  are  well  known  to  be  different  from  those 
compounds  which  are  in  the  form  of  open  chains. 

Kekule545  was  the  first  to  regard  the  aromatic  compounds  as 
derivatives  of  benzene.  He  conceived  benzene  as  a  closed  ring  of 
carbon  atoms,  the  structural  formula  he  suggested  being  the  well-known 
hexagon  which  has  been  used  so  largely  in  the  study  of  carbon  com- 
pounds. This  was  the  first  hexite  to  appear  in  chemical  literature. 

Not  only  the  constitution  of  the  direct  derivatives  of  benzene,  but 
those  of  other  substances  more  distantly  related,  such  as  napthaline, 
anthracene,  phenanthrene,  fluorescine  and  many  other  hydrocarbons, 
together  with  innumerable  and  important  derivatives,  have  been 
studied  with  most  useful  results  by  means  of  Kekule's  theory  and  a 
greater  knowledge  of  them  has  thereby  been  obtained. 

The  characteristics  of  the  organic  (carbon)  pentites  were  first 
pointed  out  by  V.  Meyer546  in  his  remarkable  researches  on  thiophenes. 

It  is  unnecessary  to  point  out  the  great  value  of  these  beginnings 
of  the  H.P.  theory  in  the  development  of  organic  chemistry  and 
for  industrial  chemistry  generally,  for  this  is  already  well  known.  It 
is  sufficient  to  state  that  Kekule's  benzene  theory  was  the  scientific 
foundation  on  which  the  methods  of  study  and  production  of  the  most 
wonderful  colours,  valuable  remedies,  deadly  poisons,  pleasant  scents, 
important  anaesthetics,  etc.,  have  been  based. 


Hexite  and  Pentites  devoid  of  oxygen 

The  H.P.  theory  indicates  that  carbon  and  silicon  can  form  hexa- 
and  penta-radicles  which  contain  no  oxygen.  In  this  connection  the 
researches  of  Manchot  and  Kieser722  are  of  interest.  These  investiga- 
tors have  shown  experimentally  the  existence  of  ring-compounds  of 
silicon  with  chromium  and  aluminium,  containing  6  Si-atoms.  They 
consider  that  the  behaviour  of  the  compound  Cr2AlSi3  towards  HF 
and  the  consequent  evolution  of  hydrogen  shows  that  the  molecular 
weight  of  this  substance  must  be  at  least  doubled  and  that  the  6  Si- 
atoms  of  the  compound  (Cr2AlSi3)2  are  unquestionably  united  to  each 
other.  These  investigators  are  thus  the  first  to  establish  beyond  all 
doubt  the  existence  of  hexa-silicon  ring-compounds,  and  their  work 
is  an  interesting  confirmation  of  the  H.P.  theory. 

It  is  also  interesting  to  observe  that  in  those  chromo-hexites  which 
are  devoid  of  oxygen,  one-third  of  the  atoms  behave  differently  from 
the  others  (pp.  269  and  292). 

The  structure  of  these  oxygen-free  compounds  may  be  made  clear 
by  means  of  the  following  structural  formula  in  which  the  Si-atoms  are 


THE   ARCHID   HYPOTHESIS  273 

directly  united  to  other  Si-atoms  and  chromium  atoms  with  other 
chromium  atoms,  the  Al-atoms  being  indicated  by  dots  : 

A/\/\  /\/\/\/\ 

SilCr   Or  I  Si  |        or          Cr   Si   Si  |  Cr  | 

\/\/\/\/  \/\/\/\/ 

•     •  •  • 

Al4Cr8Si12  Al4Cr8Si12 

According  to  the  H.P.  theory,  the  molecular  weight  of  this  com- 
pound is  at  least  twice  as  great  as  Manchot  and  Kieser  concluded  from 
their  experiments. 

When  reviewing  the  German  edition  of  the  present  work,  Manchot755 
declared  that  the  H.P.  theory  could  not  be  extended  beyond  the  chemis- 
try of  the  silicates,  but  apparently  did  not  have  the  above- 
mentioned  experiments  in  his  mind  when  he  wrote  :  "  That  the  com- 
plete neglect  of  this  portion  of  the  chemistry  of  silicon  may  lead  to 
very  erroneous  conclusions  in  regard  to  the  silicates,  the  reviewer756 
has  shown  on  a  previous  occasion." 

Manchot  here  refers  to  his  criticism  that  Pukall's  structural 
formula  for  kaolin,  which  has  a  double  bond  between  the  two  silicon 
atoms  (see  page  111),  is  not  in  accordance  with  the  behaviour  of  kaolin 
towards  hydrofluoric  acid  :  substances  with  united  silicon  atoms  must 
evolve  hydrogen  when  treated  with  HF,  whereas  kaolin  does  not. 

It  is  very  surprising  that  this  critic  instead  of  considering  whether 
the  H.P.  theory  of  the  constitution  of  aluminosilicates  might  not  throw 
light  on  his  own  investigations,  should  accuse  the  authors  of  "a 
negligence  which  may  lead  to  very  erroneous  conclusions."  It  appears 
that  he  has  quite  overlooked  the  support  which  his  own  investigations 
lend  to  the  very  theory  which  he  condemns  ! 


F.    The  H.P.  Theory  and  the  Constitution  of  the  Atoms 
The  Archid  Hypothesis. 

In  recent  years  an  ever-increasing  number  of  people  have  main- 
tained that  the  atoms  do  not  completely  fill  the  space  they  occupy,  but 
that  they  possess  "  parts."  This  view  has  long  been  held  by  those 
engaged  in  spectrolytic  investigations,  many  of  whom  hold  that  the 
atoms  slide  over  each  other  when  emitting  light ;  some  go  so  far  as  to 
say  that  some  spectrum  phenomena  indicate  a  decomposition  of  the 
atoms.  Some  physicists  even  speak  of  the  '  structure  '  of  the  atoms547 
and  consider  that  it  is  by  no  means  impossible  to  obtain  further  know- 
ledge as  to  the  internal  structure  of  atoms,  the  special  arrangement  of 
their  parts  and  the  variations  in  the  forces  of  these  parts. 

Those  who  are  interested  in  the  ionisation  theory  also  speak  of  the 
"  constituents  "  of  the  atoms,  and,  as  the  result  of  electrical  investiga- 
tions of  gases,  they  consider  that  the  negative  electrons  are  really 


274  CONSEQUENCES  OF  THE  H.P.   THEORY 

constituents  of  what  chemists  have  hitherto  regarded  as  atoms  and 
that  these  can  be  separated  by  electrical  dissociation  or  ionisation  with 
expenditure  of  different  amounts  of  energy. 

The  hypothesis  that  the  atoms  contain  "  parts  "  has  been  particu- 
larly confirmed  by  the  radio-activity  of  some  elements  discovered  by 
H.  Becquerel.  According  to  Curie548,  Becquerel549,  Rutherford  and 
Soddy550,  Re551,  Stark552  and  others,  radio-activity  is  most  satis- 
factorily explained  by  assuming  atomic  transmutations,  i.e.  the 
conversion  of  one  atom  into  another  or  into  several  others. 

The  most  recent  investigations  with  regard  to  the  chemical  nature 
of  the  elementary  atoms  thus  make  the  old  hypothesis  of  the  elements 
(which  is  the  basis  of  alchemy)  very  probable.  Moreover,  it  can 
scarcely  be  denied  that  Nature  has  produced  her  materials  in  accord- 
ance with  unitary  laws.  It  is,  therefore,  of  interest  to  endeavour  to 
discover  the  mysterious  formation  of  the  atoms  from  the  elements. 


A  Hypothesis  of  the  Constitution  of  the  Atoms 

The  smallest  particles  of  an  element  may  conveniently  be  termed 
archids  (apx*i)  ;  the  atoms  may  then  be  regarded  as  formed  of  archids 
in  a  manner  analogous  to  that  in  which  molecules  are  produced  by  the 
combination  of  a  number  of  atoms.  From  five  or  six  archid  groups, 
archid-pentites  and  archid-hexites  are  produced  respectively.  Two  or 
more  archid-hexites  or  pentites  may  also  combine  directly  or  by  the  aid 
of  other  archids.  In  this  manner  a-,  ft-  and  y-  "  archid-complexes  " 
are  formed  in  a  manner  similar  to  the  atomic  complexes. 

The  archidic  radicles,  like  the  atomic  compounds,  have  archidic 
side-chains,  and  these  limit  the  reactability  of  the  archid  compounds, 
viz.  the  atoms. 

The  combination  of  the  archids  occurs  in  accordance  with  archidic 
valencies,  as  in  the  formation  of  archid-hexite  or  -pentite,  or  of 
archidic  radicles  (hexite  and  pentite)  and  the  addition  and  formation 
of  archids  as  side-chains.  These  archidic  valencies  differ  from  the 
atomic  valencies  inasmuch  as  they  cannot  be  determined  by  any 
existing  methods.  By  the  addition  of  long  archid  chains  to  the  radicles 
or  by  the  combination  of  archidic  radicles  with  one  another  by  means 
of  archids  with  the  simultaneous  addition  of  long  archidic  chains,  the 
archidic  valencies  are  weakened  and  some  must  be  set  free,  though 
these  weak  or  free  valencies  cannot,  at  present,  be  definitely  proved  to 
exist. 

The  liberation  of  archidic  valencies  is  usually  accompanied  by  the 
evolution  of  electrical  energy  (radio-activity)  and,  after  hundreds  of 
years,  results  in  a  decomposition  of  the  atoms  or  a  transformation  of 
them  into  one  or  more  other  atoms. 

If  the  archids  are  represented  by  dots,  the  structure  of  the  atoms 
may  be  represented,  according  to  the  new  hypothesis,  as  follows  : 


THE  CONSTITUTION  OF  THE  ATOMS  275 

mm  mm 

L  '  11 

A.  m_._./'\._._m  ./K./i\. 

Ar  A,  Ar  Ar       Ar 


|  A,  | 


m 
A.  B.  C. 


m         m  m         in        m 

II  III 


m  ____          .          ----  m  ,. 

I'ArVAr2  I2  ArV  Ar       Ar 


I  I 

m         m 

E-o 
r  . 

m  m 

I  I 

I  I 

/  *\«—  •—  ,/* 
Ar    |         |    Ar 
\     /•—  •—  »\ 
\«/  \«/ 

G. 


m 

I 


Ar       Ar       Ar 


I  I  I 

•  •          • 

.A\.A\.A\. 

|3  5|5    A      3^5    .       3? 

!i       ele       ,j,       3.  ___  m',  etc.  etc. 


• 

I 
m 

H. 

The  lines  between  the  points  indicate  the  archid  valencies  ;  the 
symbols  m,  m/  and  m/x  on  the  side-chains  show  the  atomic  valencies. 
Thus,  the  atom  A  is  monovalent,  B  is  divalent  and  E  is  octovalent. 

The  Consequences  of  the  Archid  Hypothesis  and  the  Facts 
(a)  The  Valencies  of  the  Atoms. 

According  to  the  structural  formulae,  the  valencies  of  each  of  the 
atoms  B,  C  and  D  must  be  of  a  similar  kind,  those  of  the  atoms  E,  F, 
G  and  H,  on  the  contrary,  must  be  different.  In  atoms  with  side-chains 


276  CONSEQUENCES  OF  THE  H.P.   THEORY 

like  E  the  valencies  m  must  have  a  nature  different  from  the  valencies 
m' ;  in  atoms  with  side-chains  like  F  there  must  be  three  different 
kinds  of  valencies,  viz.  m,  m'  and  m". 

If,  in  atoms  of  the  type  F,  the  valency  m  is  closed  by  treatment 
at  a  high  temperature,  m'  at  a  medium  temperature,  and  m"  only  at  a 
lower  temperature,  these  atoms  would  appear  to  have  "  variable  " 
valencies  and  to  be  mono-,  tri-  or  penta-valent.  To  the  various  positions 
of  the  side-chains  in  atoms  of  the  F  type  may  be  due  the  possession  of 
electro-positive  properties  by  the  valencies  m  and  m'  and  of  electro- 
negative properties  by  the  m"  valencies  or  vice  versa.  Atoms  with 
such  side-chains  can  only  unite  with  a  definite  number  of  electro- 
positive or  electro-negative  atoms  or  atomic  groups. 

From  the  structural  formula  F  it  may  also  be  seen  that,  if  the 
valencies  m',  m,  m'  and  m"  are  saturated  and  that  one  m"  side-chain 
is  unsaturated,  the  atom  will  be  capable  of  transformation  into  the  tri-  or 
penta-valent  form,  according  to  the  power  of  the  unsaturated  valency. 

If  the  valencies  m',  m,  m'  of  the  atom  F  are  strong  (i.e.  if  they  are 
only  affected  by  treatment  at  a  high  temperature)  whilst  the  valencies 
m",  m"  are  weak  (i.e.  only  stable  at  low  temperatures)  the  atom  may  be 
said  to  have  three  major  valencies  and  two  minor  ones. 

Atoms  with  side-chains  such  as  H,  in  which  part  of  the  valency  is 
only  stable  at  low  temperatures,  may,  in  the  light  of  this  explanation, 
possess  four  minor  valencies  and  two  major  ones. 

The  minor  valencies  cease  to  exist  at  other  than  low  temperatures, 
in  concentrated  solutions  and  in  substances  in  the  solid  state,  so  that 
they  are  usually  overlooked.  The  authors  have  already  (p.  228)  stated 
that,  according  to  Knoblauch  and  Nernst,  spectrum  analysis  affords  a 
very  delicate  means  of  ascertaining  the  constancy  or  otherwise  of  the 
constitution  of  a  substance,  as  any  change  in  the  absorption  spectrum 
of  a  dissolved  substance  indicates  a  change  in  the  constitution  of  the 
latter. 

Recently  Hantzsch553  has  shown,  as  the  result  of  a  series  of  experi- 
mental investigations,  that  all  changes  hi  the  spectrum  effected  by 
dilution  are  due  to  chemical  causes  and  that  each  change  in  the  spectrum 
indicates  the  progress  of  a  chemical  reaction.  The  delicacy  of  spectrum 
analysis  is  so  great  that  the  minor  valencies  will  probably  be  discovered 
by  its  aid  in  many  cases  where  they  are,  at  present,  unknown. 

If,  in  atoms  with  four  chief  and  two  minor  valencies  (formula  H), 
only  two  or  three  of  the  major  valencies  m'  are  saturated,  such  atoms 
will  have  the  power  of  saturating  other  m'  major  valencies,  whence 
atoms  in  which  three  major  valencies  are  saturated  must  be  more 
active  in  reaction  than  those  in  which  only  two  major  valencies  are 
saturated.  The  former  must  be  better  able  to  pass  into  the  tetravalent 
state  than  the  latter,  as  the  major  valencies  m'  are  not  symmetrically 
saturated. 

These  consequences  of  the  archid  hypothesis  are  in  agreement  with 
the  known  facts  and  experimental  results. 


THE   ARCHID   HYPOTHESIS  277 

In  addition  to  atoms  of  constant  valency,  such  as  those  of  hydrogen, 
the  alkali  metals,  alkaline  earth  metals,  etc.,  there  are  atoms  with 
variable  valency  such  as  those  of  N,  As,  Sb,  P,  Fe,  Mn,  etc. 

For  instance,  in  nitrogen  atoms  the  side-chains  are  so  arranged 
that  the  five  resultant  valencies  are  of  unequal  strength  ;  three  are 
stronger  than  the  rest.  The  compound  NH4C1,  for  example,  is  unstable 
at  high  temperatures  and  is  decomposed  in  accordance  with  this 
difference  of  valency-strength  into  NH3+HC1. 

The  reasons  for  the  conclusions  drawn  from  the  structural  formulae 
just  described  are  also  confirmed  by  a  study  of  nitrogen,  as  the  atomic 
valencies  of  one  and  the  same  atom  have  different  properties,  some 
being  electro-positive  and  others  electro-negative.  J.  v.  Braun554  has 
pointed  out  this  property  of  nitrogen  and,  according  to  him,  a  penta- 
valent  nitrogen  compound  with  several  atoms  or  atomic  groups  is  only 
formed  when  the  five  radicles  necessary  are  not  of  one  and  the  same 
chemical  nature,  but  only  when  some  possess  electro-negative  properties 
(like  atoms  and  atomic  groups  which  can  act  like  anions  of  acid,  as 
Cr,  Br',  I'  CN',  NO  2')  and  others  have  electro-positive  properties  (as 
hydrogen,  hydrocarbon  residues  and  amido  groups). 

The  correctness  of  this  hypothesis  is  shown  by  the  failure  of  all 
attempts  to  produce  compounds  in  which  the  above  condition  is  not 
satisfied,  such  as  NC15,  N(C2H5)5.  In  this  connection  a  recently 
discovered  group  of  organic  substances — the  porphyrexides — is  interest- 
ing. These  are  tetravalent  derivatives  of  nitrogen  in  which  the  nitrogen 
shows  a  strong  tendency  to  combine  with  hydrogen,  and  to  pass  into 
the  trivalent  state.  This  tendency  must  necessarily  be  due  to  a 
definite  structure  of  the  nitrogen  atom. 

Other  atoms  with  variable  valencies  must  also  show  an  analogous 
behaviour.  Recently,  carbon  has  been  placed  among  those  atoms 
having  a  variable  valency.  The  side-chains  of  some  carbon  atoms  may 
be  regarded  as  occupying  positions  represented  by  formulae  E  (octo* 
valent)  and  H  (hexavalent)  the  carbon  being  then  considered  as 
possessing  four  major  and  two  minor  valencies. 

If  only  two  or  three  of  the  four  side-chains  are  saturated,  un- 
saturated  compounds  must  be  formed,  as  already  explained,  whence 
those  with  three  saturated  valencies  must  have  a  stronger  tendency 
to  be  transformed  into  the  tetravalent  state  than  those  with  two 
valencies.  Gomberg555  has  obtained  compounds  with  trivalent  carbon, 
and  Nef556  has  prepared  others  with  divalent  carbon.  In  compounds 
in  which  only  two  valencies  are  in  use,  the  carbon  shows  a  much  less 
tendency  to  pass  into  the  trivalent  state  than  in  those  in  which  three 
carbon  valencies  are  saturated.  Thus,  whilst  triphenylmethyl 
C(C6H5)3,  which  was  first  prepared  by  Gomberg,  can  only  be  isolated 
with  difficulty  on  account  of  its  enormous  power  of  reaction,  compounds 
containing  divalent  carbon  may  readily  be  produced.  These  latter  are 
powerful  reagents,  but  are  far  less  readily  converted  into  compounds 
in  which  the  carbon  has  four  valencies. 


278  CONSEQUENCES  OF  THE   H.P.   THEORY 

The  view  that  carbon  may  have  more  than  four  valencies  does  not 
agree  with  van't  Hoff's  hypothesis  that  the  affinities  of  carbon  act  as 
though  they  were  the  lines  connecting  the  centre  of  a  regular  tetra- 
hedron with  the  four  corners.  According  to  this  hypothesis,  the 
carbon  atom  has  a  maximum  of  four  valencies  and  no  minor  valencies. 
This  is,  however,  in  direct  opposition  to  the  proved  existence  of  minor 
valencies  apart  from  the  four  major  valencies. 

The  physical  isomeric  properties  of  the  "  asymmetric  "  carbon 
atom  (i.e.  the  one  to  which  four  different  atoms  or  atomic  groups  are 
attached),  such  as  optical  isomerism,  can  be  explained  by  means  of  the 
new  theory  (p.  312  et  sqq.). 

Schafer's  studies  in  connection  with  spectrum  analysis557  have 
provided  new  data  respecting  the  minor  valencies  of  carbon  and  some 
other  atoms.  Thus,  striking  colour-changes  frequently  indicate  the 
presence  of  minor  valencies,  but  they  are  best  shown  by  certain 
organo-metallic  compounds,  particularly  the  complex  salts  investigated 
by  Ley.  The  fact  that  many  compounds  of  the  heavy  metals  absorb 
normally  whilst  others  vary  greatly  in  this  respect  shows,  according  to 
Ley,  that  the  metal  in  the  latter  case  must  possess  minor  valencies  as 
well  as  the  known  major  ones.  The  metal  compounds  of  the  amio  acids 
and  ketone  acid-esters  are  interesting  in  this  connection. 

Schafer  thinks  that  a  further  proof  of  the  existence  of  minor  valen- 
cies is  to  be  found  in  the  pantochromism  discovered  by  Hantzsch558, 
i.e.  the  power  of  certain  colourless  salts  or  faintly  tinted  acids  to  com- 
bine with  various  colourless  metals  and  form  all  kinds  of  colours. 

Similarly,  Schafer  considers  that  the  presence  of  minor  valencies 
is  the  cause  of  chromotropy,  whereby  many  coloured  compounds 
(chiefly  yellow  and  red)  may  be  produced  from  indifferent  substances 
such  as  nitraniline,  quinine  and  salts  of  polynitro-compounds. 

The  fact  that  water,  alcohol,  organic  acids  and  other  oxygen 
compounds  have  a  greater  molecular  weight  at  lower  temperatures 
than  when  in  the  gaseous  state  may  also  be  best  explained  by  the 
presence  of  minor  valencies  in  the  oxygen  atoms. 

A  number  of  facts  which  seem  to  show  that  oxygen  may  have  a 
higher  valency  than  2  have  already  been  mentioned  on  page  259. 
Quite  recently,  observations  have  been  made  in  connection  with  some 
organic  compounds  which  appear  to  indicate  the  existence  of  higher 
valencies  in  oxygen.  The  most  probable  explanation  is  the  presence  of 
minor  or  weaker  valencies  of  the  oxygen.  Amongst  others  who  have 
written  about  the  higher  valency  of  oxygen — more  particularly  about 
its  "  tetravalency  "— are  Collie  and  Tickle559,  Baeyer  and  Villiger500, 
Werner561,  Kehrmann562,  Gomberg563,  Walden564,  Walker565,  Sackur566, 
and  Cohen567. 

(b)  Homologous  Series  of  Atoms. 

The  monovalent  pentites  with  the  structural  formula  A  (p.  275), 
the  divalent  archid-hexite  radicle  B,  etc.,  can  combine  with  n  new 


THE   ARCHID   HYPOTHESIS  279 

* 

archid-hexites  or  pentites,  or  m  archid-hexites  and  m'  archid-pentites 
analogously  to  the  atomic  compounds,  whereby  a  whole  series  of  mono- 
valent  or  divalent  atoms  are  produced,  as  these  new  atoms  only 
contain  one  or  two  side-chains.  In  this  manner  homologous  series  * 
may  be  formed  which  bear  some  resemblance  to  the  homologous 
series  in  organic  chemistry. 

As  there  is  a  limit  to  the  possible  number  of  archid-hexites  and 
-pentites,  the  weight  of  the  atoms  (atomic  weight)  of  each  homologous 
series  must  approach  a  definite  limit. 

Such  homologous  series  of  atoms  are  actually  known,  e.g.  the 
halogen  series,  the  alkali  metals,  the  alkaline  earth  metals,  etc.  If 
these  are  arranged  according  to  their  atomic  weights,  the  following 
series  are  obtained  : 

F  =  18.90  Cl  •=  35.18  Br  =  79.36  I  =  125.90 
Na  =  22.88  K  =  38.68  Rb  =  84.80  Cs  =  132.00 
Mg  =  24.18  Ca  =  39.80  Sr  =  86.94  Ba  =  136.40 

The  differences  between  successive  members  of  each  series  are  : 

16.28  44.18  46.54 

15.80  46.12  47.20 

15.62  47.14  49.46 

The  difference  between  consecutive  atomic  weights  is  constant, 
like  that  between  members  of  other  homologous  series  ;  in  this  case  it 
is  either  16  or  16x3. 

(c)  The  Causes  of  Radio-activity  and  the  work  of  the  Alchemists. 

The  radio-activity  of  some  elements  with  high  atomic  weights, 
such  as  radium,  uranium  and  thorium,  is  readily  explicable  in  the  light 
of  the  new  hypotheses  regarding  the  structure  of  the  atoms.  Assum- 
ing that  these  atoms  have  a  structure  analogous  to  that  of  the  H- 
atoms,  previously  mentioned,  i.e.  that  they  are  definitely  y-archid- 
complexes,  their  radio-activity  may  be  readily  explained  as  being  due 
to  their  peculiar  constitution.  The  property  these  atoms  possess  of 
radiating  electrical  energy  is  due  to  their  structure. 

From  this  it  follows  that  only  atoms  with  high  atomic  weights  can 
be  radio-active.  This  is  actually  the  case. 

The  impossibility  of  increasing  the  radio-activity  of  the  archid 
combination  by  existing  methods  of  treatment  indicates  that  enormous 
amounts  of  energy  must  be  stored  up  in  these  compounds.  Soddy568 
has  published  some  interesting  information  on  this  point  in  a  lecture 

*  When  the  members  of  a  series  of  compounds  are  similar  in  constitution  and 
chemical  properties,  but  with  the  physical  properties  undergoing  a  gradual  and  regular 
variation  as  the  molecular  weight  increases,  the  series  is  termed  homologous,  and  the 
several  members  are  said  to  be  homologues  of  one  another.  There  are  many  homo- 
logous series,  especially  among  organic  compounds. — A.  B.  S. 


280  CONSEQUENCES   OF  THE   H.P.   THEORY 

on  "  The  Present  State  of  Radio- Activity,"  in  which  the  following 
words  are  particularly  important  : 

"  Radium  evolves  for  every  gram  weight  a  hundred  calories  of  heat 
per  hour,  and  since  in  a  year  only  one  thousandth  part  changes,  it 
follows  that  the  total  energy  evolved  in  the  complete  disintegration 
of  a  gram  of  radium  must  be  enormous.  It  is  roughly  about  a  million 
times  that  given  out  by  a  similar  weight  of  coal  burning.  If  the  thirty 
milligrams  of  radium  exhibited  were  all  to  disintegrate  suddenly,  the 
effect  produced  would  equal  the  explosion  of  about  a  hundredweight  of 
dynamite.  Uranium  in  its  complete  disintegration  produced  radium, 
and  hence  the  amount  of  energy  evolved  must  be  as  much  greater  than 
in  the  case  of  radium  as  the  whole  is  greater  than  the  part.  If  we  could 
artificially  accelerate  the  rate  at  which  radium  or  uranium  disinte- 
grates, we  should  on  the  one  hand  have  achieved  transmutation  of  a 
heavier  element  into  lighter  ones,  and  on  the  other  hand  have  rendered 
available  for  use  a  new  supply  of  energy  a  million  times  more  powerful 
than  any  source  at  present  known.  The  argument  I  have  already 
stated  shows  that  if  we  succeed  in  artificially  transmuting  uranium 
there  is  little  doubt  that  the  same  means  would  be  applicable  to  the 
other  elements.  Hence  the  supply  of  energy  would  be  inexhaustible. 
But  let  us  see  what  the  old  attempt  of  the  alchemist  involved.  When 
he  was  concerned  with  building  up  a  heavy  element  like  gold  from  a 
lighter  like  silver,  he  was  attempting  a  most  profitless  task.  Frankly, 
even  if  it  could  be  done,  it  would  be  impossible  for  it  to  pay.  The 
energy  absorbed  would  cost  far  more  than  the  value  of  the  gold 
produced.  The  energy  of  some  hundreds  of  tons  of  coal  would  have  to 
be  put  into  an  ounce  of  silver  to  turn  it  into  gold.  Energy  possesses  a 
market  value  no  less  than  gold,  as  all  who  have  to  pay  electricity  bills 
realise.  So  we  may  dismiss  this  case.  But  where  he  was  attempting  to 
produce  gold  out  of  a  heavier  element  like  lead,  the  enterprise,  if  it 
had  succeeded  at  all,  would  have  been  successful  beyond  the  dreams 
of  avarice.  Not  only  would  he  have  got  the  gold  from  lead,  but  also 
a  store  of  energy  would  have  been  released  in  the  change  of  far  more 
intrinsic  and  commercial  value  than  the  gold.  Not  suspecting  this, 
perhaps  it  was  providential  for  him  that  he  failed,  or  he  might  have 
realised  the  fate  of  the  mythical  chemist  who  discovered  a  new  explo- 
sive the  secret  of  which  never  transpired  because  the  chemist  and  his 
laboratory  disappeared  simultaneously  with  the  discovery.  Actually,  the 
alchemist  in  trying  with  his  puny  appliances  to  transmute  lead  into 
gold  was  attempting  a  task  no  less  hopeless  than  that  of  a  man  attempt- 
ing to  destroy  a  battleship  with  a  percussion  cap.  Even  if  sufficiently 
potent  means  are  ever  to  hand  to  effect  the  transmutation  of  lead 
into  gold,  it  is  important  to  bear  in  mind  that  the  gold  would  be  a 
mere  by-product,  the  energy  rendered  available  would  be  the  real 
gold-mine." 


THE   ARCHID   HYPOTHESIS  281 

(d)  Radio-activity  as  a  Constitutional  Property  of  the  Atoms. 

As  radio-activity  is  due,  according  to  the  new  hypothesis,  to  the 
structure  of  the  atoms,  it  must  also  be  quite  independent  of  the 
chemical  combination  of  the  radio-active  atoms  with  atoms  of  other 
kinds,  as  well  as  independent  of  the  physical  condition  of  the  radio- 
active material,  and  must  be  impossible  to  prepare  radio-active  atoms 
artificially  by  either  synthetical  or  analytical  methods.  The  facts  are 
fully  in  agreement  with  this  consequence  of  the  theory. 

(e)  The  Transmutation  of  the  Atoms. 

From  the  authors'  hypothesis  it  follows  that  it  must  be  possible 
to  convert  one  element  A  into  another  element  B  or  to  decompose  one 
"  element  "  into  others. 

This  consequence  of  the  theory  has  been  proved  by  Sir  William 
Ramsay's  discovery  that  helium  can  be  produced  from  radium  and 
radium  from  uranium. 


Section  IV 

The  Extension  of  the  H.P.  Theory  into  a  Stereo-chemical  Theory, 
and  the  Combination  of  the  latter  with  the  Modern  Theory  of 
the  Structure  of  Crystals 

(a)  Critical  Examination  of  Existing  Stereo-chemical  Theories 

"VTEITHER  the  H.P.  theory  in  the  form  in  which  it  is  presented  on 
JJi  pages  30-38  nor  any  existing  theories  dealing  with  structural 
chemistry  can  be  regarded  as  satisfactory,  as  they  do  not  take  into 
account  the  fact  that  the  atoms  are  divisible.* 

The  weakness  of  existing  theories  of  structural  chemistry  has  long 
been  known  and  van't  Hoff569  was  the  first  to  suggest  the  importance  of 
representing  molecules  by  spatial  diagrams. 

Le  Bel570,  quite  independently,  published  a  hypothesis  concerning 
the  spatial  structure  of  atoms,  but  it  received  only  scant  attention  at 
the  time  ;  those  who  took  the  most  interest  in  it  were  the  very  men  who 
endeavoured  to  disprove  it  experimentally. 

J.  Wislicenus571  made  both  the  above  hypotheses  the  basis  of  a 
new  series  of  experimental  investigations. 

This  theory  of  spatial  structure,  which  also  deals  with  asymmetric 

*  Although  the  word  * '  atom ' '  really  means  "  indivisible ' '  its  present  use  in  chemistry 
may  be  conveniently  retained,  the  word  "  archid  "  (p.  274)  being  used  to  indicate 
the  smaller  constituents. — A.  B.  S. 


282  EXISTING  STEREO-CHEMICAL  THEORIES 

carbon  atoms,  has  been  supported  by  numerous  and  important 
results.  It  is  also  a  noteworthy  fact  that  all  optically  active  organic 
substances,  so  far  as  their  constitution  is  known,  contain  one  or  more 
asymmetric  carbon  atoms. 

Similar  speculations  have  proved  very  fruitful  in  the  investigations 
on  the  sugars  carried  out  by  E.  Fischer572. 

The  work  of  Ad.  Baeyer573  on  the  isomerism  of  the  hydrated 
phthallic  acids  also  deserves  special  attention  in  this  connection. 

In  addition  to  these  theories  various  cases  of  isomerism  of  the 
nitrogen  compounds  have  been  examined  in  connection  with  their 
spatial  relationships.  The  investigations  of  Werner  and  Hantzsch574, 
Goldschmidt575  and  others  are  important  in  this  respect. 

E.  v.  Meyer576  considers  that  the  deductions  from  observations 
have  been  pushed  as  far  as  or  even  farther  than  is  strictly  legitimate. 
As  he  rightly  remarks,577  the  greatest  disadvantage  of  the  existing 
stereo-chemical  theories  *  is  that  they  are  only  applicable  to  special 
cases  and  are  not  on  a  sufficiently  broad  basis.  They  form  a  convenient 
means  of  explaining  a  number  of  cases  of  isomerism,  but  cannot  be 
applied  to  a  general  stereo-chemistry  in  the  true  sense  of  the  words,  to 
show  the  relationship  between  crystalline  form  and  chemical  com- 
position, or  to  explain  the  various  optical,  thermal,  electrical  and  other 
physical  properties  of  crystals.  These  latter  have  been  the  subject  of 
investigations  by  a  number  of  mineralogists,  including  Schrauf578, 
Fock579,  Becke580  and  others. 

Schrauf  considers  that  the  atoms  have  definite  axial  positions  in  the 
molecules  and  that  these  form  the  basis  of  crystalline  form.  Schrauf 's 
suggestions  have  not  proved  very  fruitful  and,  according  to  Arzruni581, 
who  has  criticised  them,  the  principles  and  methods  adopted  by 
Schrauf  are  erroneous  for  this  purpose. 

Fock  sought  for  a  relationship  between  crystalline  form  and 
chemical  composition  in  a  combination  of  the  results  of  modern  stereo- 
chemistry and  general  crystallography.  According  to  him,  it  is  a 
positive  fact  that  the  affinities  of  the  atoms  do  not  merely  have  a 
definite  value,  but  operate  in  a  definite  direction.  "  Crystallography 
teaches  that  the  existence  of  a  crystal  is  due  to  its  general  properties 
varying  with  the  direction. 

"  The  conception  of  direction  is  of  different  significance  in  the 
formation  of  crystals  and  in  the  chaining  of  the  atoms,  and  leads  to 
the  thought  that  simple  relationships  may  exist  between  the  directions 
of  the  crystals." 

P.  Groth582  states  :  "  Crystals  are  usually  characterised  in  their 
physical  relationship  by  their  being  anisotropic,  i.e.  that  none  of  their 
properties  vary  in  intensity  with  the  direction  of  the  crystal  in 
accordance  with  definite  laws." 

The  simplest  and  most  natural  relationship  which  may  be  ascer- 

*  For  further  information  on  stereo -chemistry  see  No.  577  in  Appendix. 


FOCK'S   AND   BECKE'S  THEORIES  283 

tained  from  Fock's  work  is  that  the  directions  of  the  affinities  in  a 
"  crystal  molecule  "  reach  the  same  symmetry  as  that  of  the  crystal 
itself. 

By  "  crystal  molecule  "  Fock  understands  one  of  the  molecules  in 
the  crystal,  which  produces  an  aggregate  from  the  chemical  molecules. 
The  difference  between  a  chemical  molecule — which  may  be  in  the 
form  of  a  gas  or  solution — and  a  crystal  molecule — which  is  in  a  solid 
state — is  shown,  according  to  this  writer,  by  the  following  facts  : 

1 .  Fluid  or  dissolved  substances  are  chemically  active ;  crystalline 
substances  are  never  so. 

2.  Bases,  acids  and  salts  in  a  fluid  state  are  electrolytes,  but  lose 
this  property  on  crystallisation. 

3.  During   crystallisation  many   substances  take  up    "  water   of 
crystallisation." 

4.  Some  crystals  are  optically  active,  but  this  property  seldom 
remains  when  they  are  dissolved. 

If  the  existence  of  large,  independent  atomic  complexes  in  the 
crystalline  state — crystal  molecules — is  assumed,  the  foregoing  relation- 
ships are,  according  to  Fock,  capable  of  a  simple  explanation. 

As  Fock,  in  his  stereo- chemical  theory,  knew  of  no  plausible 
hypothesis  by  means  of  which  the  minimum  molecular  weight  in  the 
solid  state  could  be  explained,  he  could  not  bring  his  ideas — correct 
as  they  are — to  a  proper  conclusion,  and  his  stereo  theory  has  therefore 
proved  to  be  no  more  fruitful  than  that  of  Schrauf . 

Whether  a  polymerisation  of  gas-molecules  occurs  when  a  gas  passes 
into  the  fluid  state,  depends  on  the  number  of  chemical  molecules  in  a 
single  crystal  molecule.  P.  Groth583  distinguishes  between  chemical 
and  crystal  molecules  and,  according  to  him,  there  is  a  number  of 
facts  which  indicate  that  a  crystal  molecule  is  composed  of  a  smaller  or 
larger  number  of  chemical  molecules.  Crystals  thus  correspond  to  the 
polymerised  state  as  compared  with  the  gaseous  condition  of  single 
chemical  molecules.  Groth  calls  attention  to  Voigt's  experiments  on 
the  elasticity  of  rock-salt,  according  to  which  the  molecules  of  NaCl 
have  a  slightly  different  action  in  different  directions — a  behaviour 
which  is  incompatible  with  the  view  that  the  crystal  molecule  of  rock- 
salt  consists  of  one  atom  of  chlorine  and  one  atom  of  sodium. 

Other  writers,  as  S.  Hunt,  consider  that  calcite  and  quartz  are 
aggregates  consisting  of  584CaC03  and  948Si02  respectively.  A.  E. 
Tutton  considers  that  the  molecular  weight  of  the  smallest  crystals 
(crystal  molecules)  is  either  identical  with  that  of  the  chemical  molecule 
or  that  the  crystal  molecule  does  not  consist  of  more  than  1  to  5 
chemical  molecules.  M.  Bullouin  concludes  that  crystal  molecules 
may  contain  4  to  5  chemical  molecules.  M.  Herz757  is  of  the  opinion 
that  the  available  experimental  evidence  is  in  favour  of  the  existence 
of  substances  with  the  same  molecular  weights  in  the  solid  as  in  the 
gaseous  state  and  of  others  which  are  polymerised. 

Many  attempts  have  been  made  to  determine  the  molecular  weights 


284  EXISTING   STEREO-CHEMICAL  THEORIES 

of  substances  in  the  solid  state  by  J.  L.  Vogt758,  Doelter  and  Vucnik759. 
All  these  endeavoured  to  determine  the  molecular  weight  of  fused 
silicates  by  the  aid  of  van't  Hoff's  formula  : 

m     0.0198  T* 


In  this  formula  m  represents  the  total  number  of  grammes  of  silicate 
dissolved  in  100  g.  of  the  solvent,  M  the  molecular  weight  of  the  silicate, 
T  the  absolute  temperature,  q  the  latent  heat  of  fusion  for  1  g.  of  the 
solvent  and  t  the  depression  of  the  melting  point.  This  method  still 
leaves  undetermined  the  question  as  to  whether  the  crystal  molecule 
has  the  same  molecular  weight  as  the  substance  in  a  fused  or  dissolved 
state. 

Vogt  sought  to  determine  the  molecular  weights  of  diopsite, 
olivine  and  anorthite  in  this  manner  and  concluded  that  they  con- 
formed to  the  following  formulae  : 

CaO  •  MgO  •  2  SiO2  (Diopsite) 

2  MgO  -  SiO,  (Olivine) 

CaO  •  AlaO3  •  2  SiO,  (Anorthite)  ; 

in  other  words,  that  there  is  no  aggregation  of  molecules  in  these 
substances.  These  determinations  of  molecular  weights  have  been 
determined  in  the  same  manner  by  Doelter  and  M.  Vucnik759,  but 
these  investigators  reached  entirely  different  conclusions  and  were  of 
the  opinion  that  the  application  of  the  van't  Hoff  formula  to  fused 
silicates  is  not  free  from  objection,  on  account  of  the  few  determinations 
of  q  which  have  been  made.  The  determinations  of  T  are  only  reliable 
between  20°  and  30°.  It  is  not,  therefore,  surprising  that  Doelter  and 
Vucnik  found  that  the  results  obtained  by  this  method  disagreed  with 
the  formulae  in  eight  cases  out  of  nine. 

Doelter  has  not  expressed  any  doubt  as  to  the  solid  silicates  being 
polymerised  compounds,  and  he  has,  indeed,  pointed  out  that  if  the 
van't  Hoff  formula  is  retained  the  results  obtained  from  it  agree  much 
more  closely  with  multiple  than  with  single  formulae.  According 
to  Doelter,  an  extensive  polymerisation  occurs  when  aluminous 
silicates  pass  into  the  solid  state,  as  is  shown  by  the  great  heat  of 
crystallisation. 

Van't  Hoff761  has  expressed  the  opinion  that  the  solid  state  is  not 
characterised  by  the  formation  of  a  complex  molecular  structure,  but 
that  in  solid  solutions  the  facts  appear  to  show  that  the  molecules  are 
of  the  simplest  possible  constitution  and  not  greater  than  twice  the 
molecular  weight  ordinarily  stated.  This  view  is  based  on  studies  of 
isomorphous  mix-crystals  which  it  is  assumed  are  in  the  state  of  solid 
solutions.  Positive  proof  of  the  non-polymerisation  of  the  molecules 
in  solid  solutions  has  not  yet  been  published  ;  on  the  contrary,  many 
facts  are  quite  opposed  to  this  view. 

Becke584  has  criticised  Fock's  theory  in  a  manner  which  demands 


MOLECULAR   WEIGHTS   OF   CRYSTALS  285 

further  investigation.  According  to  him,  in  endeavouring  to  explain 
what  relationship  exists  between  crystalline  form  and  chemical  com- 
position, special  attention  must  be  paid  to  symmetry  as  this  is  the 
most  obvious  factor  common  to  both  stereo-chemistry  and  crystallo- 
graphy. In  Fock's  theory  this  is  not  the  case. 

Becke's585  attempt  to  explain  stereo-chemically  the  cause  of  the 
hemihedrism  *  of  calcspar  and  magnesite  and  of  the  tetrahedrism  t 
of  dolomite  and  ankerite  is  of  special  value.  He  started  with  the 
Bravais-Sohncke  theory  of  crystalline  structure,  but  instead  of 
extensionless  points  he  imagines  symmetrical,  corporeal  molecules  or 
molecular  groups  as  forming  a  kind  of  lattice-work.  Nevertheless, 
F.  Becke  has  only  been  able  to  apply  his  partially  developed  ideas  to 
a  few  cases,  and  as  he  has  suggested  no  hypothesis  to  explain  the  mini- 
mum molecular  wreight  in  the  solid  state,  his  ideas  do  not  admit  of 
general  application.  According  to  L.  Brauns586,  the  method  adopted 
by  Becke  in  attempting  to  ascertain  the  relative  position  of  the  atoms 
in  space  may  result  in  representing  symmetry  in  the  form  of  a  stereo- 
chemical  formula. 

(b)  The  Modern  Theory  of  Crystalline  Structure  and  the  Possibility  of 
its  Combination  with  Structural  Chemical  Theories 

The  work  of  Fock  and  Becke  in  connection  with  the  formulation  of  a 
stereo-chemical  theory  would  probably  have  been  crowned  with  quite 
different  results  if  the  leading  structural  chemical  theories  were  in  as 
complete  agreement  with  the  available  experimental  material  as  is  the 
case  with  the  H.P.  theory,  or  if  the  existing  stereo-chemical  theories 
had  been  placed  on  a  broader  basis.  Hence  it  seemed  worth  while  to 
endeavour  to  convert  the  H.P.  theory  into  a  general  stereo-chemical 
theory  and  to  combine  it  with  the  results  of  crystallography.  This 
would  appear  to  be  the  best  method  of  solving  the  problem  as  to  the 
relationship  between  crystalline  form  and  chemical  composition. 

The  fact  that  a  series  of  physical  properties  of  crystals  shows  a 
definite  arrangement  in  the  smallest  particles,  has  stimulated  a  number 
of  investigators  such  as  Bravais587,  Frankenheim588,  and  Sohncke589  to 
attempt  to  find  the  laws  connecting  the  theoretical  spatial  relations  of 
observed  crystalline  forms  to  the  corresponding  symmetries. 

If  the  limiting  faces  of  crystals  are  conceived  as  lying  in  three 
axes  which  meet  in  a  point  but  are  not  in  a  single  plane,  the  crystalline 
forms  of  any  substance  may — as  is  well  known — be  expressed  in  terms 
of  the  lengths  of  these  axes  and  of  the  angles  between  them.  It  is 
also  supposed  that  the  smallest  particles  of  which  crystals  are  com- 
posed lie  along  the  same  axes  in  accordance  with  definite  laws,  thus 

*  Hemihedrism  is  the  formation  of  half  the  number  of  faces  possessed  by  the  com- 
plete forms  of  crystals  of  the  same  series. 

t  Tetrahedrism  occurs  when  a  crystal  has  only  one  quarter  of  the  number  of 
faces  possessed  by  the  primary  form. 


286 


THE   STEREO-HEXITE-PENTITE   THEORY 


forming  the  various  crystal  forms.  The  generally  accepted  explanation 
of  crystalline  structure  originated  in  this  manner. 

If  this  theory  of  crystalline  structure  is  to  be  combined  with  a 
structural  chemical  theory,  atoms  or  groups  of  atoms  must,  clearly, 
be  conceived  in  place  of  the  formless  points.  These  points  then  become 
the  centres  of  gravity  of  the  various  atoms  or  atomic  groups.  The 
place  in  which  these  "  points  "  are  found  is  their  average  plane  of 
equilibrium,  as  the  atoms  and  molecules  are,  as  a  result  of  their  heat- 
content,  in  a  state  of  constant,  oscillatory  motion. 

None  of  the  ordinary  structural  chemical  theories  can  be  combined 
in  a  simple  manner  with  the  general  theory  of  crystalline  structure. 
This  combination  is  possible,  however,  as  soon  as  the  H.P.  theory  is 
extended  into  a  stereo-chemical  one. 

(c)  Stereo-hexites  and  Stereo-pentites.  or  a  Stereo-chemical  Theory 
In  a  geometrical  double  pyramid  of  the  form  P  : 

C 


the  two  bases  of  the  pyramids  are  identical. 

In  this  bi-pyramid  P,  CF  is  represented  by  (7,  AD  by  A  and  BE  by  B, 
the  axes  of  which  cut  each  other  in  0.  The  lines  OA,  OB  and  OC  are 
represented  by  a,  b  and  c  and  the  angles  COB,  COD  and  BOD  by  a, 
ft  and  y.  The  axes  CF,  AD  and  BE  are  termed  chemical  axes,  the 
ratio  a  :  b  :  c  is  termed  the  "  chemical  parameter  ratio  "  and  the  angles 
a,  /3  and  y  are  termed  the  angles  of  the  chemical  axes. 

In  a  given  hexite,  such  as  the  compound  6  Si02,  the  atomic  groups 


THE   POSITION   OF  THE   ATOMS   IN  SPACE 


287 


Si02  may  be  arranged  at  each  of  the  six  corners  of  the  double  pyramid 
P.  The  valencies  between  the  Si02  molecules  are  partly  in  the  direc- 
tion of  the  diagonals  of  the  hexagon,  i.e.  in  the  direction  of  the  chemical 
axes,  and  partly  in  the  direction  of  the  edges  of  the  double  pyramid. 
It  is  clear  that  in  a  hexagon  only  a  portion  of  the  possible  valencies 
can  be  represented  : 

C 


B 


E 


D 


F 


If  the  atomic  groups  of  a  pentite  radicle  5  Si02  are  supposed  to  be 
distributed  in  space,  this  must  be  doubled  and  a  double  pyramid  P' 


described  in  which  the  bases  ABDE  and  A'B'D'E'  do  not  coincide, 
but  are  parallel  to  each  other,  though  the  distance  between  them  is 
infinitely  small.  At  the  corners  of  this  pyramid  (P'),  which  possess  a 
common  chemical  axis  CF  which  cuts  the  other  parallel  chemical  axes 
AD,  BE  and  A'D',  B'E'  in  the  points  0  and  O',  the  atomic  groups  of 
two  pentites  are  found. 

The  straight  lines  OA,  O'A',  and  OB,  O'B'  are  each  respectively 


288 


THE   STEREO-HEXITE-PENTITE   THEORY 


equal,  and  may  be  represented  by  a  and  b.  The  straight  line  OC  is 
equal  to  O'F  and  may  be  represented  by  c.  The  pentites  thus  have  a 
chemical  parameter  ratio  a  :  b  :  c  and  the  angles  of  their  chemical  axes 
are  analogous  to  those  in  the  hexites  a,  /3  and  y. 

A  compound  of  the  composition  6A1203-  12Si02  may  be  repre- 
sented diagrammatically  by 


|  Si  |  Al  |  Al  |  Si 


or 


B 


B 


E 


D       B 


E 


F 


i.e.  the  atomic  groups  in  a  molecule  consisting  of  several  hexites  may 
be  conceived  as  analogous  to  those  of  a  hexite  divided  in  space.  The 
following  facts  should  be  observed  : 

1.  All  the  atomic  groups  (A12O3  and  Si02)  marked  C  and  F  in  the 
compound  in  question  are  found  on  the  axis  CF,  whereby  each  four 
Al2O3-groups,  as  shown  by  the  structural  formula,  must  lie  near  to 
each  other,  two  pairs  of  SiO2-groups,  on  the  contrary,  are  further  apart 
from  each  other. 

2.  All  the  atomic  groups  (A1203  and  SiO2)  marked  A  and  D  are  on 
the  axis  AD  whereby  the  A12O3-  and  SiO2-groups  are  situated  precisely 
the  same  as  those  on  the  axis  CF. 

3.  The  atomic  groups  marked  B  and  E  are  distributed  along  the 
axis  BE  in  an  analogous  manner  as  in  1  and  2. 

4.  Each  six  atomic  groups — either  Si02  or  A12O3 — of  the  com- 
pound are  bound  by  valency  forces  to  their  position  in  space,  as  is 
shown  by  the  structural  formula  :   special  valency  forces  between  the 
Si-  and  the  Al-radicles  are  also  in  operation,  as  may  be  seen  from  the 
structural  formula.    With  such  an  arrangement  in  space  of  the  hexite 
units,  it  must  clearly  occur  that  the  distances  between  the  atoms  of 
the  two  Al-hexites  and  of  the  two  Si-hexites  in  the  compound  are 
unequal.     Nevertheless,  the  difference  in  the  distances  between  the 
atoms  or  atomic  groups  of  the  various  Al-  and  Si-hexites  is  so  extremely 
small  that  the  different  Al-  and  Si-hexites  in  the  compound  may  be 
regarded  as  fully  analogous. 

5.  A  study  of  the  aluminosilicates  and  allied  chemical  compounds 
shows  that  side-chains  (basic,  constitutional,  water  of  crystallisation, 
etc.)  may  be  attached  in  the  direction  of  the  axes  CF,  AD  and  BE. 

6.  If  atoms  or  atomic  groups  occur  at  the  point  O  (Fig.  P),  i.e. 


THE   STRUCTURE   OF  CRYSTALS  289 

in  the  point  at  which  the  three  chemical  axes  cut  each  other,  and  are 
combined  by  valency  forces  with  two,  or  n,  hexites  or  pentites,  the 
/#-  and  y-complexes  are  formed  (pp.  76  and  241). 

7.  The  chemical  parameter  ratio  a  :  b  :  c  and  the  size  of  the  angles 
a,  /3  and  y  form  the  chemical  constants  and  depend  upon  the  size  of  the 
valency  forces  between  the  atomic  groups. 

(d)  The  Hexite-Pentite  Law 

The  valency  forces  between  the  hexite-  and  pentite-units  and 
the  radicles  themselves  (the  hexites  and  pentites)  of  various  sub- 
stances are  very  variable  ;  in  many  compounds  they  are  so  feeble 
that  the  existence  of  the  hexite-pentite  law  has  naturally  been  over- 
looked until  the  present. 

It  is  highly  probable  that  very  many  compounds  (both  simple  and 
complex)  of  widely  different  elements,  such  as  carbon,  silicon,  alu- 
minium, iron,  chromium,  manganese,  the  halogens,  nitrogen,  oxygen, 
etc.,  exist  in  the  form  of  hexites  and  pentites  or  in  combinations  of 
these — as  has  already  been  shown  in  the  present  work.  This  implies 
that  this  arrangement  of  the  atoms  is  neither  a  mere  coincidence  nor  a 
property  of  only  a  few  substances,  but  of  matter  generally,  and  on  this 
the  hexite-pentite  law  is  based  and  has  proved  to  be  of  great  value  in 
stereo-chemistry . 

The  hexite  and  pentite  form  is  not  characteristic  of  only  a  few 
compounds  (aluminosilicates,  silico-molybdates,  metal-ammonias,  etc.) 
but  of  matter  generally.  Each  chemical  compound  in  the  solid  state 
is  composed  of  hexites  or  pentites  or  combinations  of  them,  the  atoms 
or  atomic  groups  being  arranged  in  space  in  the  manner  indicated. 
In  this  manner  major  and  minor  valencies  occur. 

(e)  The  Combination  of  the  Stereo-Hexite-Pentite  Theory  and  the  Modem 
Theory  of  the  Structure  of  Crystals 

The  stereo-hexite-pentite  theory  mentioned  above,  and  for  the 
sake  of  brevity  termed  the  "  S.H.P.  theory,"  may  easily  be  combined 
with  the  theory  of  crystalline  structure  published  by  Bravais,  Franken- 
heim  and  Sohncke,  by  substituting  the  units  of  hexites  and  pentites 
for  the  formless  "  points  "  in  the  latter  theory. 

Frankenheim590,  in  his  theory  of  the  structure  of  crystals,  has 
regarded  these  points  as  molecules  from  which  the  crystals  form. 
Sohncke591,  in  his  theory  of  the  atomic  construction  of  matter,  also 
used  the  word  "  point  "  as  meaning  "  molecule."  Sohncke  sought  to 
prove  by  a  priori  arguments  that  if  the  atomic  construction  of  matter 
is  the  cause  of  the  structure  of  crystals,  only  the  present  known  systems 
of  crystals  can  exist,  no  others  being  possible. 

The  hexite  and  pentite  units  are  not  equidistant  from  each  other, 
as  different  affinities  exist  between  them,  especially  if  the  substance 
under  consideration  is  composed  of  units  of  different  natures.  The 


290     CONSEQUENCES   OF  STEREO-HEXITE-PENTITE   LAW 

distances  between  the  various  units,  and  particularly  the  differences 
in  these  distances,  are  so  extremely  small  that  they  may  be  regarded  as 
equidistant.  If  it  is  assumed  that  all  the  "  molecular  lines  "  AD,  BE 
and  CF,  on  which  the  hexite  and  pentite  units  are  distributed,  are  in 
parallel  groups  (i.e.  all  the  AD  lines  are  parallel  to  all  the  AB  lines 
and  so  on)  and  that  the  "molecular  planes"  ABDE  and  A'B'D'E' 
are  parallel  to  each  other,  the  so-called  "  network  "  and  "  regular 
system  of  points,"  i.e.  the  theory  of  crystalline  structure,  follows.592 

Limits  of  space  prevent  a  more  detailed  description  of  the  generally 
accepted  theory  of  the  structure  of  crystals  ;  this  can  be  obtained 
from  the  published  literature  on  the  subject.  It  may,  however,  be 
noted  that  this  theory  is  generally  accepted  because  it  is  in  full  agree- 
ment with  numerous  properties  of  crystals.  Thus  it  was  found,  as  a 
result  of  this  theory,593  that  altogether  14  kinds  of  parallelopipedonal 
arrangements  are  geometrically  possible  and  that  only  seven  classes  of 
crystals  can  exist  which  can  be  distinguished  by  their  symmetry.  This 
result  is  in  agreement  with  experience.  The  seven  different  arrange- 
ments in  space  of  the  molecules  show  the  same  symmetrical  ratios, 
as  the  seven  classes  of  crystals  show  in  regard  to  cohesion. 

It  may  be  inferred  a  priori  that,  as  this  theory  of  crystalline 
structure  does  not  postulate  any  bonds  (affinity  forces)  between  the 
units  of  the  crystal,  i.e.  between  the  atoms  or  atomic  groups,  and  pays 
no  regard  to  the  nature  of  these  units,  it  cannot  explain  many  of  the 
constitutional  properties  of  crystals.  Thus,  according  to  the  "  network 
theory  "  all  crystals  which  crystallise  regularly  must  be  optically 
iso tropic,  yet  such  crystals  are  known  which  are  optically  diaxial.  i.e. 
anisotropic.  This  theory  also  fails  to  explain  other  properties  of 
crystals  which  are  probably  of  a  constitutional  nature,  such  as  the 
difference  in  behaviour  of  a  crystal  in  two  different  positions  such  as 
is  shown  by  its  solution  and  change  of  temperature  under  the  action  of 
an  electric  current,  and  by  the  existence  of  two  crystals  built  in 
opposite  ways  and  polarising  circularly  in  opposite  directions.  Sohncke 
endeavoured  to  explain  this  last  property  crystallographically  by 
means  of  new  hypotheses. 

As  previously  explained,  it  is  possible  to  combine  the  stereo-hexite- 
pentite  theory  with  the  modern  theory  of  the  structure  of  crystals.  It 
is  by  no  means  improbable  that  the  weaknesses  in  the  modern  theory 
of  the  structure  of  crystals  may  be  overcome  by  its  combination  with 
the  S.H.P.  theory.  To  ascertain  this  it  is  now  necessary  to  see  how 
the  facts  agree  with  the  S.H.P.  theory. 

(/)  The  Stereo-Hexite-Pentite  Theory  and  the  Facts 
A.  Di-  and  Poly-morphism  and  Hauy's  Law 

It  follows  from  the  theory  that  a  given  compound  such  as  CaCOj 
may  exist  in  either  the  hexite  or  pentite  form  if  it  is  in  the  solid  state. 
The  minimum  molecular  weight  of  this  substance  when  in  the  solid 


DI-  AND  POLY-MORPHISM  291 

state  may  therefore  correspond  to  (CaC03)6  or  (CaC03)10,  or  if  both 
hexite  and  pentite  radicles  exist  in  the  same  molecule,  other  compounds, 
such  as  (CaC03)16,  (CaCO3)22,  etc.,  are  possible.  The  actual  existence 
of  simple  acids  and  salts  in  the  form  of  hexites  and  pentites  has  been 
shown  in  a  number  of  cases  in  the  chapter  on  "  The  H.P.  Theory  and 
the  Constitution  of  Simple  Acids  "  (p.  268).  In  the  following  formulae, 
which  may  lead  to  a  theoretical  minimum  of  molecular  weight,  it  will 
be  found  that  simple  salts  may  consist  of  hexites  and  pentites  and 
their  combinations  : 

In  this  connection  the  composition  of  the  following  borates594  is 
interesting  : 

Boronatrocalcite NaaO  •  2  CaO  •  5  B203  •  12  H80 

Ascharite 6  MgO  •  3  B203  •    2  H20 

Pandermite  2  CaO  •  3  B2O3  •    3  H2O 

Colemanite 2  CaO  •  3  B203  •    5  H2O 

Franklandite     Na20  •  CaO  •  3  B203  •    7  H80 

Hydroboracite Mgo  •  CaO  •  3  B203  •    6  H2O 

Larderellite   2  (NH4)20  •  8  B2O3  •    8  H2O 

Kaliborite    K2O  •  4  MgO  •  11  B203  •  12  H20 

The  minimum  molecular  weight  of  some  phosphates,  arsenates  and 
vanadates  may  be  found  from  the  composition  of  the  minerals  of  the 
apatite  group  :595 

f9CaO-3P205    -CaFl2 

Apatite    ^  9  CaO  •  3  P2O5    •  CaCl2 

[9CaO-3P205   -Ca(Cl,Fl)2 

Pyromorphite   9  PbO  •  3  P205    •  CaCla 

Polyspharite   9  R"O  •  3  P2O5    •  CaCl2  (R"=Pb,  Ca) 

Mimetesite 9  PbO  •  3  As2O5  •  PbCl2 

Kampylite     9  PbO  •  3  RjO,  •  PbCl2  (RV=P,  As) 

Vanadinite 9  PbO  •  3  V206   -  PbCl2 

Endlichite   9  PbO  •  3  Rj05  •  PbCl2  (Rv=As,  Vd) 

Hexites  and  pentites  may  also  be  formed  from  the  molecules  Si02, 
TiO2,  Zr02,  Fe2O3,  A1203  and  from  the  atoms  S,  Se,  P,  C,  etc.  All 
these  substances,  when  in  the  form  of  hexites  or  pentites,  have, 
nevertheless,  the  empirical  formulae  Si02,  Ti02,  etc.  Hence  such 
hexites  and  pentites  must  be  distinguished  from  each  other  by  means  of 
their  crystalline  form,  hardness,  specific  gravity,  behaviour  towards 
reagents,  etc.  In  a  certain  sense  it  may  be  stated  that  the  substances 
CaCO3,  Si02,  TiO2,  etc.  are  di-  or  poly-morphous ;  in  reality  they  form 
chemically  different  substances. 

This  consequence  of  the  theory  may  be  fully  and  completely  proved 
by  the  facts.  From  the  large  amount  of  published  information 
respecting  polymorphous  substances596  the  following  may  be  quoted  : 

Calcium  carbonate  ("  CaCO3  ")  :  hexagonal-rhombohedric  as  calcite 
(calcspar),597  rhombic  as  aragonite.598 

Strontium  carbonate  ("  SrC03  ")  :   dimorphous.599 

Silica  ("  Si02  ")  :  hexagonal-trapezohedric-tetratohedric  as  quartz, 


292    CONSEQUENCES  OF  STEREO-HEXITE-PENTITE  THEORY 

hexagonal  as  a-tridymite,601  rhombic  as  /3-tridymite.  Von  Lasaulx602 
and  Schuster603  have  regarded  /6-tridymite  as  triclinic  ;  Mallard604,  on 
the  contrary,  has  shown  that  /3-tridymite  crystallises  rhombically  and 
Arzruni605  and  Groth606  agree  with  him.  Silica  also  crystallises  regularly 
as  a-cristobalite607  and  tetragonally  as  jS-cristobalite.608 

.  Titanic  oxide  ("  Ti02  ")  :  tetragonal  as  rutile,609  tetragonal  as  anas- 
tase,610  rhombic  as  brookite611  or  arkansite  and  as  edisonite.612  Haute- 
feuille613  has  prepared  anastase  artificially  at  860°,  brookite  between 
860°  and  1000°  and  rutile  at  a  higher  temperature. 

Svlphur  ("  S  ")  :  rhombic,614  a-monoclinic,615  /3-monoclinic,618 
y-monoclinic  (?),617  hexagonal618  and  as  "black  sulphur."619 

Ferric  Sulphide  ("  FeS2  ")  :  regular  pentagonal  hemihedric  as 
pyrite,620  rhombic  as  marcasite.621 

An  interesting  light  is  thrown  by  the  S.H.P.  theory  on  the  cause  of 
the  dimorphism  of  the  compounds  with  the  empirical  formula  FeS2. 
These  sulphides  may  be  compared  with  oxygen  compounds  from 
which  the  oxygen  has  been  removed.  For  instance,  the  following 
compounds,  with  the  ratio  B  :  S  =  1  :  2  are  theoretically  possible  : 

(a)  1  J  R"0  •  3  R2'"0,  •  15  SO, 

(b)  3  R2'"03  •  12  SO, 

(c)  3R"0     •    6  SO, 

If  the  oxygen  is  struck  out  and  Fe"  is  substituted  for  R"  and  Fe'"  for 
R'",  the  following  compounds  will  be  produced  : 

(a)  1  J  Fe"  •  3  Fe/"  •  15  S  =  7.5  FeS2 

(b)  3  Fe/"  •  12  S  =±  6    FeS2 

(c)  3  Fe"    •    6  S  =  3    FeS2 

In  other  words,  three  different  compounds  with  the  empirical  formula 
FeS2  are  possible.  In  the  first,  one-fifth  of  the  iron  must  be  present 
in  the  ferrous  state,  the  remainder  being  ferric  ;  in  the  second  all  the 
iron  is  in  the  ferric  state,  and  in  the  third  compound  the  whole  of  the 
iron  is  in  the  ferrous  state. 

According  to  Brown622,  only  one-fifth  of  the  iron  in  pyrite  is  in  the 
ferrous  state,  whilst  in  marcasite  it  is  all  in  this  state,  i.e.  the  structural 
formula  a  is  that  of  pyrites,  and  c  is  that  of  marcasite.  The  b  form  of 
FeS2  is  not,  at  present,  known.  Brown  assigns  to  pyrite  the  following 
improbable  formula  : 

Fe 


I        I 
F       Fe    Fe      Fe 


^\    /\  /\ 

S  S—  S  SS  S—  S  S 

Other  metals  whose  compounds  occur  in  "  ous  "  and  "  ic  "  states  — 
such  as  cobalt,  nickel,  etc.  —  must  form  analogous  compounds  with  the 


DI-   AND  POLY-MORPHISM  293 

general  formula  RS2.     In  short,  compounds  with  the  general  formula 
RS2  must  be  di-  or  poly-morphous. 

This  treatment  of  the  sulphides  leads  to  new  ideas  as  to  their 
constitution,  and  it  would  be  interesting,  did  space  permit,  to  calculate 
the  formulae  from  the  analyses  of  such  compounds  and  to  study  their 
properties  in  the  light  of  this  theory. 

The  simple  elements  Se,  P,  As,  C,  Sn,  Zn,  Fe,  Ir,  Pd,  Ag,  etc.,  occur 
in  various  forms,  as  do  also  the  compounds:  (NH4)2SiFl6,  K2SnFl8, 
ZnS,  HgS,  FeS2,  Ag3SbS3}  Fe203,  Sb2O3,  As203,  NH4NO3,  KN03, 
LiN03,  Al203-Si02,  Na20-Al203-3SiO2,  Na20  •  A1203  •  4Si02, 
K20  •  A1203  •  2  Si02,  CaO  •  A1203  •  2  SiO2,  etc. 

According  to  the  S.H.P.  theory  each  chemical  compound  in  the 
solid  state  must  have  its  own  definite  a  :  b  :  c  ratio  and  its  own  a,  ft  and 
y  angles  ;  i.e.  it  must  have  its  own  crystalline  form.  According  to  this 
theory  it  is  improbable  that  a  single  substance  can  change  its  crystal- 
line form.  This  agrees  in  a  remarkable  way  with  the  law  stated  by 
the  well-known  mineralogist  Hauy623  in  1801,  to  the  effect  that  "  one 
and  the  same  substance,  in  a  chemical  sense,  can  occur  in  only  one 
form." 

Berthollet624  opposed  Hauy's  view  and  suggested  that  the  forms  of 
crystals  are  accidental  and  are  independent  of  their  chemical  com- 
position. In  support  of  this  he  referred  to  the  two  minerals  aragonite 
and  calcite,  which  have  both  the  same  chemical  composition  (CaC03), 
yet  differ  in  crystalline  form.  Hauy  next  suggested  that  the  difference 
in  the  crystalline  form  of  these  two  minerals  might  be  due  to  the 
presence  of  strontium  in  aragonite,  though  he  failed  to  find  strontium 
in  some  aragonites,  and  was  eventually  obliged  to  abandon  this 
suggestion.  In  spite  of  opposition,  Hauy  refused  to  abandon  his 
"  law  "  and  maintained  that  the  calcspar-aragonite  problem  must  be 
capable  of  some  other  explanation.  Since  1821,  however,  Hauy's  law 
has  been  neglected  on  account  of  the  discovery,  in  that  year,  by 
Mitscherlich625  of  two  forms  of  sodium  phosphate  H2NaP04  •  H20. 

Mitscherlich626  held  that  any  substance  —  elementary  or  compound 
—  can  occur  in  two  different  crystalline  forms.  This  view,  which  was 
based  on  the  occurrence  of  two  sodium  phosphates  with  the  formula 
H2NaPO4  -  H2O  and  of  various  elements  in  several  forms,  is  clearly 
incorrect,  as  de  facto  these  are  chemically  different  compounds,  all 
of  which  possess  the  same  empirical  formula. 

It  was  only  towards  the  close  of  the  nineteenth  century  that  a 
number  of  investigators  concluded  that  Hauy's  law  is  correct.  Thus, 
Geuther627  endeavoured  to  find  the  cause  of  the  dimorphism  of  CaCO3 
in  the  existence  of  a  "  di-carbonic  acid  "  H4C206  and  a  "  mono  -carbonic 
acid  "  H2C03  ;  he  assigned  to  calcite  and  aragonite  the  following 
structural  formulae  : 


Calcite. 


294   CONSEQUENCES  OF  STEREO-HEXITE-PENTITE  THEORY 

•nd  " 


Aragonite. 

The  credit  for  an  explanation  of  di-  or  poly-morphism  by  means 
of  an  assumption  which  agrees  with  the  S.H.P.  theory  is  due  to 
O.  Lehmann628.  This  is  based  on  numerous  experiments.  He  concluded 
that  the  chemical  molecules  within  the  physical  molecule  are  combined 
with  each  other  —  even  though  loosely  ;  and  that  different  modifications 
of  a  polymeric  substance  are  really  different  substances. 

As  the  result  of  his  experiments,  Lehmann  was  led  to  a  "  re- 
discovery "  of  Hauy's  law  which  he  stated  in  the  following  terms  : 

1.  No  substance  has  more  than  one  crystalline  form.     If   two 
substances  have  different  crystalline  forms  they  are  different  substances 
chemically,  no  matter  whether  they  are  atomic  or  molecular  compounds. 

2.  No  substance  has  more  than  one  state  of  aggregation.    The  so- 
called  "  three  states  "  of  aggregation  of  some  substances  really  repre- 
sent three  chemically  different  substances. 

B.   Isomorphism  in  the  light  of  the  S.H.P.  Theory 

Substances  which  are  chemically  related  and  those  having  an 
analogous  constitution  must  clearly  be  related  in  their  crystalline 
form.  Such  a  connection  between  the  crystalline  form  and  chemical 
composition  may  be  inferred  from  the  S.H.P.  theory,  but  its  existence 
was  discovered  as  early  as  1819  by  Mitscherlich629.  Whilst  examining 
phosphates  and  arsenates  Mitscherlich  observed  that  the  salts  of  both 
phosphoric  and  arsenic  acids  frequently  have  the  same  form  ;  he 
concluded  that  the  chemical  and  crystalline  forms  are  interdependent 
and  proposed  the  term  "  isomorphism  "  for  this  phenomenon. 

From  the  S.H.P.  theory  it  also  follows  that  isomorphous  compounds 
have  similar,  but  not  absolutely  identical  chemical  and  geometrical 
constants  (a  :  b  :  c  and  a,  /3,  y).  As  the  geometrical  constants  depend 
on  the  valency  forces  between  the  units  and  these  vary  with  different 
units,  the  geometrical  constants  of  analogously  constituted  substances 
which  contain  somewhat  different  constituents  must  clearly  show 
certain  differences.  Hence,  if  the  substances  have  not  precisely  the 
same  composition  they  cannot  be  regarded  as  of  identical  crystalline 
form  even  though  they  are  apparently  quite  isomorphous.  Groth630 
has  shown  that,  with  more  accurate  instruments,  the  angles  of  crystals 
of  isomorphous  substances  are  found  to  be  very  nearly,  but  not  abso- 
lutely, equal  to  each  other. 

The  isomorphism  discovered  by  Mitscherlich  was  found  to  occur  in 
all  mineral  groups,  and  such  minerals  are  therefore  arranged  into 
groups  of  crystallographically  related  substances.  Amongst  the  most 
important  of  these  are  the  widely  distributed  minerals  of  the  felspar 
group,  which  have  a  remarkable  resemblance  to  each  other  in  their 
crystalline  form  and  other  physical  characteristics.  Schuster's631 


ISOMORPHISM  295 

investigations  have  shown  that  in  a  large  number  of  felspars  (plagio- 
clases)  the  optical  properties  show  these  substances  to  be  capable  of 
arrangement  in  a  definite  series. 

Under  the  name  "  tourmaline  "  are  grouped  a  number  of  minerals 
which,  with  the  instruments  available,  appear  to  agree  completely  in 
their  crystalline  form  and  are,  therefore,  regarded  as  isomorphous. 
Mica,  clintonite,  etc.,  form  similar  groups.  Chemists  and  mineralogists 
have  been  very  energetic  in  endeavouring  to  explain  the  isomorphism 
of  such  minerals  in  terms  of  chemical  structure,  but  so  far  they  have 
found  no  generally  satisfactory  solution  to  this  problem.  Thus, 
Rammelsberg632,  as  early  as  1850,  pointed  out  a  relationship  between 
the  monoclinic  orthoclase  and  the  triclinic  minerals  albite,  oligoclase, 
labradorite  and  anorthite.  According  to  him  these  minerals  closely 
resemble  each  other  in  their  geometrical  form  and  do  not  differ  from 
each  other  more  than  do  other  isomorphous  substances.  They  also 
show  a  great  similarity  in  their  physical  properties,  but  chemically 
they  show  such  differences  that  "  chemists  consider  that  a  separation 
is  essential."  On  another  occasion  Rammelsberg633  pointed  out  the 
similarity  of  the  tourmalines  crystallographically,  though,  according 
to  him,  they  are  quite  unrelated  chemically.  In  his  opinion,  the 
tourmalines  consist  of  silicates  of  varying  degrees  of  saturation  which 
are  combined  in  different  ways  and  yet  are  isomorphous,  i.e.  they  are 
of  very  similar  form. 

In  order  to  explain  the  relationship  between  the  crystalline  form 
and  the  chemical  composition  of  minerals  of  the  felspar  group,  Tscher- 
mak  assumed  that  the  felspars  were  isomorphous  mixtures  of  two 
silicates — albite  and  anorthite — to  which  he  gave  the  following  formula : 

Albite     NaAlSiSi208 

Anorthite  . . .  .CaAlAlSi208 

All  triclinic  felspars  are,  according  to  Tschermak,  simply  mixtures 
of  albite  and  anorthite  in  all  imaginable  proportions,  so  that  a  con- 
tinuous series  is  possible.  Although  this  felspar  theory  has  proved  of 
great  value  for  the  systematic  study  of  analyses  of  the  felspars,  it  has 
been  powerfully  opposed  from  several  sides.  As  a  matter  of  fact, 
there  is  always  some  K,  Mg,  and  ferrous  and  ferric  iron  in  felspars  which 
do  not  occur  in  the  mixtures  ;  i.e  the  felspars  cannot  contain  these 
substances  if  they  are  simply  mixtures  of  albite  and  anorthite.  After 
prolonged  discussion,  extending  over  some  years,  Tschermak's  theory 
is  now  accepted  by  most  mineralogists,  particularly  since  Schuster634 
has  shown  that  the  plagioclases  may  be  made  to  form  a  series  based  on 
their  optical  properties  and  that  for  each  composition  of  the  limiting 
members  there  is  a  definite  optical  behaviour  which  is  reminiscent  of 
either  albite  or  anorthite.635 

As  the  miscibility  of  albite  and  anorthite— which  are  not  analogous 
in  their  chemical  composition — appears  plausible  from  a  chemical 
point  of  view,  attempts  have  been  made  in  other  directions  to  find 


296    CONSEQUENCES  OF  STEREO-HEXITE-PENTITE  THEORY 

structural  formulae  for  the  mixed  members  of  the  felspars  —  albite  and 
anorthite  —  so  that  they  appear  to  have  a  chemical  as  well  as  a  crystallo- 
graphic  relationship.  For  instance,  Clarke636  has  suggested  the  follow- 
ing formulae  : 

/[Si,OJ  ss  Na8  /[Si04]  =  Ca  Ca  =  [Si04]x 

AlAsiaOe]  33  Al  Alf-[Si04]  =  Al  Al  ^  [Si04HAl 
\[Si,08]  ss  Al  \[SiO  J  33  Al  Al  ss  [SiO  J/ 

Albite.  Anorthite. 

Here  he  clearly  assumes  the  possibility  of  an  isomorphous  replace- 
ment of  the  tetravalent  groups  (Si04)  and  (Si308).  Groth637,  on  the 
contrary,  suggests  the  folio  whig  formulae  for  the  same  substances  : 


Q.  Q. 

Si\0_Al/°\Si  =  0          "No—Al—  0-A1  =  0 
\O/  \ 

o  o          \o 

1/0—  Na  I  /o—  Ca 

SS0  Sl^o 

Albite.  Anorthite. 

Attempts  have  also  been  made  to  explain  the  relationship  between 
the  crystalline  form  and  the  chemical  composition  of  the  tourmalines 
on  the  assumption  that  hypothetical  members  of  the  series  exist. 
Jannasch638  has  given  the  following  simple  formula  for  the  "  isomor- 
phous mixture  series  '  '  : 

Si  Si 


O  O  0  0\     /O  O  O  O 
R  R  R  |  RR  R 


This  does  not  agree  with  all  the  ratios  of  Si02 :  B2O3  actually 
found  in  tourmalines.  Clarke639,  on  the  contrary,  assumes  the  following 
hypothetical  members  for  the  tourmaline  series  which  are  analogously 
constituted ;  these  approach  more  closely  to  the  actual  facts  : 

I.  II. 

/Si04  =  Rs  /Si04  SB  MgH 

AU_Si04  ss  Al  Alf^iO4  ss  MgH 
\Si04  =  Al  —  B02  \SiO4  =  Al  —  B02 

I  I 

Al  —  B03  =  NaH  Al  —  B03  =  NaH 

I  I 

/Si04  =  Al  —  B02  /SiO4  =  Al  —  B02 

Alf-Si04  33  Al  Al^-Si04  =  Al 

\Si04  33  Al  \Si04  33  Al 


ISOMORPHISM 


297 


III. 

/Si04  =  MgH 
Alf-Si04  =  MgH 
\Si04  =  Al  —  B02 

Al  —  B03  =  NaH 

/Si04  =  Al  —  B02 
Al^-Si04  =  MgH 
\Si04  35  Al 


IV. 

/Si04  ss  MgH 
Si04  s=  MgH 
Si04  =  Al  —  B02 

Al  —  B03  =  NaH 

/Si04  =  Al  —  B02 
Al^-Si04  =  MgH 
\Si04  3=  MgH 


It  is  interesting  to  see  what  is  the  genetic  relationship  between  all 
the  members  of  the  felspar  groups,  both  crystallographically  and 
physically,  in  the  light  of  the  S.H.P.  theory.  The  calculation  of  the 
formulae  of  a  large  number  of  analyses  of  the  felspar  group  (see 
Appendix)  shows  that  they  may  be  regarded  as  salts  of  the  following 
acids  : 

I      II 
. / 

— <j3i    R  !  Si 


I      I 


I       I 
\/\/\_ 

Si    R    Si    Si  |  R    Si 


B. 


C. 


D.    (a) 


D.    (6) 


i.e.                              A.  8  H2O  •  5  A12O3  •  22  SiO2 

B.  7  H2O  •  5  A12O3  •  24  SiO2 

C.  9  H20  •  6  A12O3  •  20  Si02 

D.  12  H20  •  6  A1203  •  24  Si02 

Two  isomeric  compounds  D  are  shown  ;    isomers  of  the  other 
hydrates  are  clearly  possible. 

As  has  already  been  shown,  each  of  these  types  can  produce  a 


298  CONSEQUENCES  OF  STEREO-HEX ITE-PENTITE  THEORY 

whole  series  of  hydrates.  Strictly  speaking,  the  formulated  felspars  of 
these  different  types  are  salts  of  various  hydrates. 

The  hydrates  here  mentioned  are,  in  a  certain  sense,  the  maximal 
hydrates  of  the  felspars  of  these  types,  with  a  maximum  proportion  of 
"  water  of  constitution  "  or  of  acid  hydroxyls. 

From  this  representation  of  the  structure  of  the  felspars  the 
following  inferences — which  are  in  agreement  with  previous  experi- 
ments— may  be  drawn  : 

1.  There  is  a  genetic  relationship  between  the  various  members  of 
the  series,  both  physically  and  chemically,  i.e.  there  is  a  similarity  in 
their    crystallographic,    optical    (see    Schuster)    and    other   physical 
properties. 

2.  The  proportion  of  potassium,  magnesium  and  iron  (the  last 
named  in  various  states  of  oxidation)  in  some  felspars  is  appreciable. 

3.  The  maximum  proportion  of  base  -f  water  of  constitution  in 
some  felspars  is  explicable  ;  e.g.  the  presence  in  salt  50  of  the  A  type 
of  6  MO  -  2  H2O  ;  the  presence  of  7  MO  •  5  H2O  in  No.  145  of  type  D 
and  of  9  MO  •  3  H20  in  No.  146  of  the  same  type  (see  Appendix). 

4.  These  structural  formulae  also  provide  an  explanation  how  it  is 
that  if  the  content  of  base  is  divided  as  in  formula  a  (C  axis)  a  different 
system  will  be  produced  than  would  occur  if  the  base  were  in  the 
positions  shown  in  b  (i.e.  nearer  the  A  and  B  axes) ;  i.e.  the  formation  of 
monoclinic  and  triclinic  felspars  may  be  readily  understood.     The 
formula  b  is  that  relating  to  the  triclinic  felspars. 

The  general  crystalline  form  of  a  large  number  of  compounds,  such 
as  those  of  type  a,  is  explicable  by  means  of  their  common  kernel  or 
core. 

Analogous  relationships  are  also  observable  in  the  minerals  of  the 
tourmaline  group  (see  Appendix). 

It  is  interesting  to  note  that  Retgers640  had  previously  suggested 
that  the  isomorphism  of  the  members  of  various  silicate  groups  may  be 
completely  explained  by  means  of  a  large,  common  kernel  or  core. 
"  If  we  regard  them  as  containing  such  a  molecular  core,  it  is  at  once 
clear  that  the  secondary  atoms  may  be  regarded  as  chemically  analo- 
gous. No  matter  whether  the  molecules  which  adhere  to  the  large  core 
are  small,  like  H20,  CaO  or  NH3,  or  whether  they  contain  6  or  7 
molecules  aq.,  the  chief  fact  is  that  the  common  core  reveals  itself 
clearly  in  the  crystalline  form." 

These  opinions  on  the  constitutions  of  the  felspars,  tourmalines, 
etc.,  were  not  without  influence,  for  even  simple  compounds  of  which 
the  analyses  lead  to  simple  formulae  have  been  regarded  by  many 
writers  as  though  they  were  mixtures,  i.e.  as  composed  of  substances 
mixed  in  capricious  proportions  and  not  combined  in  stoichiometrical 
quantities.  Others  have  regarded  substances  as  "  isomorphous 
mixtures  "  even  when  they  have  shown  them  to  be  composed  in 
definite  stoichiometrical  proportions.  As  an  instance  of  this  the 
"  mix-crystals  "  of  sulphurous  salts  investigated  by  Fock641  may  be 


ISOMORPHISM 


299 


mentioned,  particularly  the  ammonium  salts  (NH4)20  •  S205  •  1JH20, 
and  the  salts  with  the  general  formula  R"O  •  S205  •  J  H20  (where 
R"=Zn,  Cd,  Fe,  Ni,  Co  and  Mn)  which  Fock  has  examined  crystallo- 
graphically.  In  spite  of  the  fact  that  these  "  mix-crystals  "  contain 
their  various  constituents  in  stoichiometrical  proportions,  Fock 
regarded  them  as  "  isomorphous  mixtures." 
The  following  salts  were  obtained  by  Fock  : 


I. 

1. 

4 

(NH 

4)20 

• 

ZnO 

•    5 

S 

2o 

5 

2 

4 

(NH 

4/  2^-^ 

• 

FeO 

•    5 

S 

2o 

5 

3. 

4 

(NH 

4)20 

• 

NiO 

•    5 

s 

2o 

5 

4 

4 

(NH 

4)2O 

• 

CoO. 

•    5 

s 

2o 

5 

5. 

4 

(NH 

4/  2^-' 

• 

MnO 

•    5 

s 

2o 

5 

II. 

6. 

3 

(NH 

4)2O 

•2CdO 

•    5 

s 

2o 

5 

III. 

7. 

16 

(NH 

4/  2^-^ 

•6 

FeO 

•22 

s 

2o 

5 

IV. 

8. 

18 

(NH4)20 

•  4 

ZnO 

•22 

s 

2o 

5 

On  re-calculating  Fock's  figures  the  following  Table  is  obtained  : 


Compound 

(NH4),O 
per  cent. 

HO 

per  cent. 

(NH4)2S20« 
•1J  HZ0 
per  cent. 

BSjO, 
•1JH.O 

per  cent. 

Total 

Mol.- 
ratio 

NH4  •  Zn-Salt 

(a)  Tabular  crystals 

18.47 

6.39 

79.19 

19.90 

99.09 

4    1 

18.64 

6.44 

79.93 

20.07 

100.00 

(b)  Prismatic  crystals  . 

18.82 

5.82 

80.71 

18.12 

98.83 

9    2 

19.02 

5.92 

81.57 

18.43 

100.00 

(NH4)  •  Cd-Salt        .          . 

14.34 

16.40 

61.50 

38.36 

99.86 

3    2 

13.97 

17.15 

59.89 

40.11 

100.00 

NH4  •  Fe-Salt 

(a)  Crystal  from  the  solution 

16.81 

8.12 

72.09 

27.43 

99.52 

8    3 

1  FeO  :  1  (NH4)2O  . 

17.11 

7.88 

73.36 

26.64 

100.00 

(b)  Crystal  from  the  solution 

18.73 

5.89 

80.32 

19.90 

100.22 

4    1 

1  FeO  :  4  (NH4)2O  . 

18.77 

5.77 

80.51 

19.49 

100.00 

NH4-Ni-Salt 

18.64 

5.74 

79.94 

18.86 

99.00 

4    1 

18.73 

5.97 

80.34 

19.66 

100.00 

NH4-  Co-Salt       .... 

18.69 

5.73 

80.15 

18.86 

99.01 

4    1 

18.73 

5.97 

80.34 

19.66 

100.00 

NH4-Mn-Salt      .... 

18.41 

5.63 

78.95 

19.23 

98.18 

4    1 

18.79 

5.69 

80.58 

19.42 

100.00 

The  molecular  ratios  shown  above  differ  slightly  from  Fock's  ;  he 
obtained  a  series  corresponding  chiefly  to  4  (NH4)20  •  R"O  •  5  S2O5. 
According  to  him  the  geometrical  ratios  of  these  salts  are  : 


Compound 


a :  b :  c 


NH4 

Zn  Salt 

2.0597 

1 

.2042 

90°  52' 

NH4 

Cd  Salt 

2.1299 

1 

.2263 

90°  49' 

NH4 

Fe  Salt 

2.0564 

1 

.1907 

90°  51' 

NH4 

Ni  Salt 

2.0643 

1 

.2077 

90°  56' 

NH4 

Co  Salt 

2.0594 

1 

.2045 

90°  54' 

NH4 

mi 

Mn  Salt 

n 

•t 

2.1289 

1 

: 

1.2173 

90°  19' 

5»             1               A 

These  figures  do  not  indicate  "  isomorphous  mixtures,"  but 
definite  chemical  compounds  in  which  may  clearly  be  seen  the  charac- 
teristic which  is  so  often  observed  in  pentites,  viz.  that  one-fifth  of 
the  units  behave  differently  from  the  remainder. 


300  CONSEQUENCES  OF  STEREO-HEXITE-PENTITE  THEORY 

Rammelsberg642  has  also  shown  that  the  components  of  "  iso- 
morphous  mixtures  "  have  a  relatively  simple  relationship  to  each 
other  ;  from  this  he  concluded  that  they  must  be  regarded  as  molecular 
compounds  with  a  simple  and  rational  molecular  ratio. 

The  influence  of  Tschermak's  theory  of  the  constitution  of  some 
felspars  has  been  very  great  and  some  chemists  and  mineralogists  have 
even  used  it  to  explain  the  crystallographic  relationship  between  the 
members  of  a  series  of  other  complex  silicates.  In  this  way,  the 
minerals  of  the  scapolite  group  with  its  end-members  consisting  of 
mejonite  Ca4AlaSi6025  and  marialite  Na4Al3Si9024Cl ; 643  the  amphibole 
group  with  actinolite  (Mg.  Fe)3CaSi4Oi2  and  syntagmatite  (R"3R'"2- 
Si3012)644  as  end  metals,  the  clintonite,  mica,  orthochlorite  and  other 
groups  have  been  regarded  as  isomorphous  or  morphotropic645 
mixtures.  No  one  appears  to  have  been  troubled  by  the  thought 
that  many  of  the  so-called  mix-crystals  of  this  series  are  still  un- 
known. 

Rammelsberg646  sharply  protested  against  this  generalisation  of 
Tschermak's  theory  with  which  he  did  not  agree,  but  he  was  unable  to 
convince  many  people  of  the  truth  of  his  protest.  It  is  clear  that,  if  the 
Tschermak  theory  were  correct,  it  would  be  of  general  application  and 
would  not  apply  to  merely  a  single  group  of  minerals,647- 648  as  is  found 
to  be  the  case.  The  great  difficulty  in  the  way  of  accepting  the  theory 
that  these  substances  are  isomorphous  mixtures  is  to  be  found  in  some 
facts  which  this  theory  cannot  explain  and  which  are  in  direct  con- 
tradiction to  it.  Thus,  Retgers649  endeavoured  to  produce  mix- 
crystals  from  the  salts  KH2P04  and  NH4H2P04,  and  according  to  this 
theory  he  should  have  obtained  an  "  unbroken  series  of  mixtures." 
As  a  matter  of  fact,  he  was  only  able  to  obtain  "  mixtures  "  containing 
100  to  80  per  cent,  of  potassium  salt  to  0  to  20  per  cent,  of  the  ammonium 
salt,  and  20  to  0  per  cent,  of  the  former  to  80  to  100  per  cent,  of  the 
latter.  He  could  not  obtain  any  intermediate  compound  containing 
75  to  25  per  cent,  of  the  potassium  salt  and  25  to  75  per  cent,  of  the 
ammonium  salt.  In  endeavouring  to  prepare  mix-crystals  of  KC103 
and  T1C103  the  same  investigator650  again  failed  to  obtain  a  continuous 
series.  The  crystals  produced  contained  either  0  to  36-3  or  97*93  to  100 
molecular  per  cents  of  the  first  salt.  Between  these  limits  of  36-3 
and  97- 93  there  was  a  gap  of  nearly  62  molecular  per  cents.  H. 
Schultze651  in  preparing  mix-crystals  of  PbMo04  and  PbCr04  has 
found  that  these  only  unite  in  certain  definite  proportions. 

Negative  results  have  also  been  obtained  by  several  other  investi- 
gators such  as  Wyrouboff652  with  (NH4)2S04  and  (NH4)2Cr04, 
Topsoe653  with  BeS04  •  4  H2O  and  BeSe04-  4  H20.  No  explanation 
of  these  facts,  which  are  in  direct  opposition  to  the  theory  of  isomor- 
phous mixed  crystals,  has  yet  been  found.  Yet  these  facts  are  not 
merely  explicable  by,  but  are  direct  consequences  of  the  H.P.  theory 
when  the  following  are  taken  into  consideration  : 

1.  Tammann's  chemical  and  physio-chemical  investigations  have 


ISOMORPHISM  301 

shown  that,  in  accordance  with  the  H.P.  theory,  the  OH-groups  in  the 
hydrates 

/— /|!N— \ 

I      \X      I 

1  11 

(a)  (b)  ^c) 

3  H20  •  3  P206          5  H20  •  5  P205  5  H20  •  8  P2O6 

behave  differently  ;  in  a  J,  in  b  i,  and  in  c  f  behave  differently  from 
the  remainder  (see  pp.  268  and  269).  For  this  reason  Tammann  was 
only  able  to  obtain  from  the  hydrate  a  the  salts  Na2O  •  2  K2O  •  3  P205 
and  K20  •  2  Na20  •  3  P205,  and  could  not  prepare  J  Na20  •  2|-  K20  • 
3  P2O5  and  &  K2O  •  2  J  Na2O  -  3  P205  in  this  manner. 

Further,  in  these  alkali-salts  of  the  hydrate  o,  only  J  of  the  base 
conducts  positive  electricity  and  K4(PO3)6  passes  off  as  an  anion. 

In  the  compound  (NH4)20  •  4  (NH4)2O  •  5  P2O5,  J  of  the  base 
behaves  differently  from  the  remainder  (p.  269)  both  chemically  and 
physio-chemically.  Thus,  only  £  of  the  (NH4)2O  can  be  replaced  by  a 
base,  the  compounds  (NH4)2O  •  4R^O  -  5P2O5  (R'=Na,  Li)  being 
formed  ;  only  ^  of  the  base  atoms  conduct  electricity.  From  the 
composition  3  R"0  •  2  Na2O  -  8  P2O5  (R"=Mg,  Ca,  Mn)  it  may  be 
seen  that  in  the  hydrate  c,  f  of  the  base  behave  differently  from  the 
rest. 

2.  The  minerals  of  the  epidote  group  have  the  general  formula  : 

2  H20  •  8  CaO  •  6  R2"'03  •  12  Si02          (R"'  =  Al,  Fe), 
and  the  structural  formula  : 


In  the  R-hexites,  J  of  the  R-atoms  must  clearly  behave  differently 
from  the  others.  As  a  matter  of  fact,  the  end-members  of  this  mixed 
series  (see  Appendix)  are  : 

I        I 
'' 


Si    Al     Al   Si 


:J|       i      ii 
2  H20  •  8  CaO  •  5  A1203  •  Fe203  •  12  Si02 
and 

II 


=|  Si  |  Fe  |  Fe  |  Si  |_ 

II       I        "       II 
2  H20  •  8  CaO  •  4  Fe203  •  2  A12O3  •  12  Si02 

Members  with  5.5  A1203  •  0-5  Fe2O3  or  5  Fe2  03  •  A1203  are  unknown. 


302   CONSEQUENCES  OF  STEREO-HEXITE-PENTITE  THEORY 

These  facts  lead  to  the  conclusion  that,  in  many  cases,  the  pro- 
duction of  a  continuous  series  of  mixtures  without  any  gaps  is  chemi- 
cally impossible.  In  this  way  the  experimental  results  obtained  by 
Retgers,  Schultze,  Wyrouboff,  Topsoe  and  others  may  not  only  be 
explained,  but  can  actually  be  predicted  from  the  H.P.  theory.  For 
instance,  Schultze's  experiments  on  the  production  of  mix-crystals  from 
PbMoO4  and  PbCrO4  lead  to  the  result  shown  in  the  following  Table  : 


Constituents 

Mol.  % 

Mols. 

Mol.  % 

Mols. 

Mol.  % 

Mols. 

Crystalline 

Colour 

PbMoO4  and 
PbCrO4 

74 

12 

66 

4 

58 

3 

Y  tetragonal 

red 
yellow 

26 

4 

34 

2 

42 

2 

PbMoO4  and 
PbCrO4 

27 

6 

10 

2 

— 

— 

I  monoclinic 

73 

16 

90 

18 

— 

— 

Schultze  thus  obtained  two  series  of  salts  which  may  be  distinguished 
by  their  crystalline  form  and  colour,  viz  : 


I. 


II. 


1. 

2. 
3. 
4. 
5. 


16PbO 

6PbO 

5PbO 

22PbO 

20PbO 


12  Mo03 
4Mo03 
3Mo03 
6Mo03 
2Mo03 


4Cr08 

2Cr03 

2Cr03 

16  CrO, 

18  CrO, 


The  difference  in  the  crystalline  form  and  the  colour  of  the  crystals 
obtained  from  a  mixture  of  PbMo04  and  PbCr04  can  be  explained. 
These  properties  are  closely  related  to  the  chemical  constitution  of 
these  substances  :  the  tetragonal  form  and  red  colour  are  character- 
istic of  hexites  and  pentites  in  molybdenum  compounds  in  which  this 
metal  is  partly  replaced  by  Cr,  and  the  monoclinic  form  and  yellow 
colour  are  natural  to  chromium  hexites  and  pentites  in  which  part  of 
the  metal  has  been  replaced  by  Mo.  There  is  also  another  good  reason 
why  Schultze  could  not  obtain  a  continuous  series  of  mixtures  from 
lead  molybdate  and  chromate,  viz.  in  Mo-  and  Cr-hexites  and  pentites 
one  portion  of  the  atoms  behaves  differently  from  the  others  on  substitu- 
tion. This  behaviour  is  clearly  shown  in  the  compounds  obtained  by 
Schultze. 

The  present  fashion  for  considering  that  "  isomorphous  mixtures  " 
are  not  chemical  compounds  is  partly  due  to  the  influence  of  Ber- 
th ollet654,  who,  starting  with  the  idea  that  chemical  reactions  depend 
on  the  masses  present,  reached  the  conclusion  that  in  a  compound 
consisting  of  two  or  more  atoms  the  extent  to  which  the  reaction 
proceeds  will  depend  on  the  number  of  atoms  available,  provided  that 
no  special  conditions  interfere  with  the  mass-action.655  From  this 
conclusion,  Berthollet  argued  that  substances  usually  enter  into 
combination  in  variable  quantities  according  to  the  conditions  under 
which  the  reaction  occurs. 

Proust  opposed  this  view  of  Berthollet's  and  the  difference  between 


ISOMORPHISM  303 

them  was  eventually  ended  by  the  definite  proof  of  the  constancy  of 
the  combinations.  It  appeared,  however,  as  if  Nature  had  produced 
both  "  privileged  "  (combined  in  stoichiometrical  proportions)  and 
"unprivileged"  compounds  (isomorphous  mixtures  which  are  not 
combined  in  definite  proportions  and  obey  the  mass-law  of  Berth  ollet). 
This  is  not  the  case  ;  on  the  contrary,  Nature  has  formed  all  definite 
compounds — including  the  so-called  "  mixtures  " — according  to  one 
and  the  same  law. 

The  following  observations,  made  by  John  Hunter,  with  regard 
to  the  harmony  and  obedience  to  definite  laws  which  are  always  found 
in  Nature  are  well  worth  quoting  here  : 

"  How  often  we  stumble  against  what  we  think  are  irregularities  in 
Nature  !  How  often  we  fancy  that  the  chain  is  broken  just  because  we 
cannot  see  each  link  in  the  chain  and  because  the  incompleteness  of 
our  knowledge  prevents  our  seeing  the  symmetry  of  the  whole  !  When- 
ever it  is  given  to  a  man  to  see  harmony  where  previously  only  discord 
was  apparent,  or  to  find  a  relationship  where  formerly  it  was  only 
guessed  at  but  could  not  be  proved,  then,  in  my  opinion,  is  it  the 
urgent  duty  of  such  an  one  to  show  the  harmony  he  sees  in  natural 
phenomena.  He  should  do  this  for  many  reasons,  not  the  least 
important  of  which  is  that  the  discovery  of  such  harmony  gives  us  all 
courage  to  tread  the  path  of  Truth.  The  discovery  of  new  harmony, 
however  small,  lifts  for  a  moment  the  shadow  which  ordinarily  over- 
hangs the  Truth  and  hides  it  from  our  gaze." 

These  golden  words  of  so  great  a  scientist  often  recur  to  the  minds 
of  the  authors  of  the  present  volume,  when  they  realise  that,  at  last, 
it  has  been  permitted  to  them  to  remove  completely  the  artificial 
division  set  up  by  Proust,  more  than  a  century  ago,  when  he  divided 
matter  into  "combinations"  and  "dissolutions,"  the  former  including 
definite  chemical  "  compounds  "  and  the  latter  molecular  "  combina- 
tions "  in  which  the  proportions  appeared  to  be  so  irregular  as  to  be 
the  sport  of  chance,  i.e.  substances  which  do  not  appear  to  obey  the 
law  of  constant  proportions. 

Soon  after  Proust  had  set  up  this  artificial  division  (i.e.  his  system- 
atic classification  of  matter  into  compounds  and  "  mixtures  "),  Ber- 
thollet  opposed  it  and  asked  the  following  pertinent  questions  : 
"Wherein  shall  we  seek  the  reason  why  the  '  compounds '  are  formed 
by  the  uniting  of  their  constituents  in  constant  proportions,  whilst  in 
4  combinations '  the  ratios  are  variable  and  apparently  due  to 
chance  ?  Is  the  force  which  effects  the  union  of  a  metal  with  sulphur 
or  oxygen  different  from  that  which  forms  more  complex  substances 
out  of  these  simpler  compounds  ?  " 

From  the  nature  of  these  two  questions  it  is  clear  that  Berthollet 
was  fully  convinced  of  the  essential  unity  of  the  natural  law  involved. 
There  is  an  old  philosophical  dictum  natura  nonfacit  saltum,  quoted  by 
Darwin  in  introducing  his  Theory  of  Descent, in  respect  of  the  Harmony 
which  pervades  the  Cosmos,  about  which  Newton  wrote  in  so  illumin- 


S04  CONSEQUENCES  OF  STEREO-HEXITE-PENTITE  THEORY 

ating  a  manner,  and  regarded  by  Berthollet,  in  his  classical  "  Essai  de 
statique  chimie,"  as  applying  with  equal  truth  to  the  world  of  atoms. 
This  idea  was  so  firmly  fixed  in  the  mind  of  Berthollet  that  he  did  not 
hesitate  to  oppose  Proust's  dualistic  conception  and  to  insist  on  the 
unity  of  the  force  of  chemical  attraction.  At  the  same  time,  it  is  only 
fair  to  state  that  Proust  himself  recognised  something  of  the  truth  in 
Berthollet's  contention  when  he  wrote  :  "  I  do  not  wish  to  press  this 
matter  unduly  lest  I  lose  my  way  in  a  place  which  is  not  too  brightly 
illuminated  by  facts.  The  forces  which  produce  both  kinds  of  com- 
pounds may  or  may  not  be  the  same,  but  it  is  at  least  true  that  the  re- 
sults are  so  different  that  they  must  not  be  grouped  indiscriminately,  even 
though  Nature  itself  has  placed  only  an  indefinite  line  between  them." 

Since  it  has  been  shown  in  innumerable  cases  that  the  law  of 
constant  proportions — which  Proust  applied  to  only  a  limited  number 
of  substances — is  capable  of  indefinite  extension  since  Dalton's 
discovery  of  the  law  of  multiple  proportions,  the  statement  of  Ber- 
thollet quoted  above  becomes  increasingly  important  and  efforts 
should  be  made  with  increasing  earnestness  to  establish  the  general 
application  of  the  Proust-Dalton  law.  Even  if  this  cannot  yet  be 
accomplished  because  of  the  many  substances,  such  as  glass,  colloids, 
etc.,  which  are  regarded  as  solid  solutions,  it  does  not  prove  exceptions 
to  natural  laws,  for  no  such  exceptions  can  exist ;  it  is  merely  the 
incompleteness  of  chemical  theory  which  prevents  the  natural  laws 
involved  from  being  properly  understood  or  defined  so  far  as  these 
apparent  exceptions  are  concerned. 

It  is  certainly  surprising  that  none  of  the  critics  have  pointed  out 
this  advantage  of  the  H.P.  theory,  and  it  is  even  more  remarkable 
that  Allen  and  Shepherd  should  consider  it  a  drawback  of  the  theory. 
Thus,  they  state  in  their  review  of  the  German  edition  of  this  work: 737 
"  An  important  fact  in  this  connection  has  been  .  .  .  completely 
overlooked.  We  are  now  in  possession  of  many  facts  which  show  that 
it  is  never  wise  to  assume  that  silicates  are  chemical  compounds.  For 
instance,  to  take  a  well-known  example,  the  felspars  are  solid  solutions 
and  any  theory  of  structure  to  be  complete  must  show  the  permanency 
which  is  characteristic  of  the  properties  of  true  compounds  as  distinct 
from  the  maxima  and  minima  of  mere  groupings."  These  critics 
further  state  that:  "The  authors  never  distinguish,  and  this  is  most 
important,  between  purely  chemical  changes  and  changes  of  an 
entirely  physical  nature." 

The  reply  to  these  statements  is  that  there  is  no  need  specially  to 
distinguish  between  chemical  compounds  and  the  so-called  isomorphous 
mixtures  or  solid  solutions,  as  the  distinction  is  perfectly  clear  !  It 
would  also  have  been  much  better  if  the  critics  had  quoted  at  least  a 
few  of  the  "  many  facts  which  show  that  it  is  never  wise  to  assume 
that  silicates  are  chemical  compounds,"  so  that  the  precise  value  of 
this  statement  of  theirs  might  be  ascertained.  As  only  the  felspars  are 
mentioned,  any  criticism  must,  for  the  moment,  be  restricted  to  these. 


INFLUENCE  OF  SIDE-CHAINS  ON  CRYSTALLINE  FORM    305 

Now,  on  studying  the  structural  formulae  of  the  felspars  (p.  297) 
carefully,  it  is  easy  to  see  that  almost  without  exception  they  are 
referable  to  one  type.  These  formulae  also  show  how  various  sub- 
stances in  other  groups  of  siliceous  compounds  can  be  formed  from 
the  felspars  or  vice  versd  ;  they  indicate  the  physical  relationship  of  all 
these  compounds  with  reference  to  crystalline  form,  optical  properties, 
specific  gravity,  etc.  On  the  other  hand,  the  assumption  that  felspars 
are  "  solid  solutions  "  explains  none  of  these  things.  How  can  Allen 
and  Shepherd  explain  in  the  light  of  then*  theory  of  solid  solution  the 
properties  of  felspars  which  are  described  in  paragraphs  numbered  2, 
3  and  4  on  page  298  ?  For  what  reasons  should  the  felspars  be  treated 
in  a  different  manner  from  other  silicates  and  not  regarded  as  definite 
chemical  compounds  ?  Is  the  force  which,  in  the  case  of  certain 
silicates,  forms  definite  chemical  compounds,  different  from  that  which 
forms  the  so-called  "  solid  solutions  "  from  simple  silicates  ? 

Many  fights  between  chemical  dualism  and  monism  have  occurred 
in  the  past  and  the  victory  has  always  been  completely  in  favour  of 
monism.  Sooner  or  later,  the  dualistic  conception  of  the  constitution 
of  compounds,  which  was  published  by  Proust  more  than  a  century 
since,  will  go  the  way  of  all  other  dualistic  theories. 

C.  The  Dependence  of  the  Geometrical  Constants  on  the  Side-chains 
It  has  been  repeatedly  shown  in  previous  pages  (cf.  p.  216)  that 
the  addition  of  bases,  "  water  of  constitution  "  or  "  water  of  crystal- 
lisation," in  the  form  of  side-chains  to  hexites  or  pentites  weakens  the 
bond  between  the  units  forming  the  hexites  or  pentites,  whilst  their 
removal  or  splitting  off  strengthens  the  bonds.  In  other  words,  by 
adding  bases  in  the  form  of  side-chains,  part  of  the  valencies  in  the 
ring  or  core  is  destroyed.  According  to  the  S.H.P.  theory,  this  must 
influence  the  geometrical  constants  a  :  b  :  c  and  a,  ft  and  y.  Crystallo- 
graphic  experiments,  previously  made,  are  in  agreement  with  this 
consequence  of  the  theory. 

The  influence  of  the  "  water  of  crystallisation  "  on  the  crystalline 
form  of  a  compound  has  long  been  recognised  ;  thus,  the  metallic  sul- 
phates with  5  H2O  are  known  to  differ  in  form  from  those  with  7  H20. 
In  this  connection  a  series  of  uranium-acetates  prepared  by  Rammels- 
berg656  are  interesting.  These  have  the  general  formula  : 


Ac 


U     I         "aq., 

I — ,/r 


ArN'r 


or 


r — 


Ac 


U 


aq. 


r         (r= J  RO) 
A.  B. 


306   CONSEQUENCES  OF  STEREO-HEXITE-PENTTTE  THEORY 

3  RO  •  6  U03  •  9  (CH3CO)20  •  aq.      3  RO  •  6  U03  •  9  (CH3CO)20  •  aq. 
R  =  Mg,  Zn,  Ni,  Co,  Cd,  Ca,  Sr,  (NH4)2,  Kt>  Ag2. 

Of  the  possible  compounds  of  this  series,  Rammelsberg  prepared 
the  following  : 

a  :b  :  c 

1.     3  MgO  •  6  UO.  •  9  (CH3CO)20  •  12  H  rhombic  0.7468  :  1  :  0.5082 

3MnO  -6U08-9(CH3CO)20-12H  „  0.7536:1:0.4957 

II.     3  MgO  -6U08-9(CH3CO)20-    7H  „  0.8946:1:0.9924 

3ZnO  -6U08-9(CH3CO)20-    7H  „  0.8749:1:0.9493 

3  NiO  •  6  UO3  •  9  (CH3CO)20  •    7  H  „  0.8670  :  1  :  0.9500 

3CoO  -6U03-9(CH3CO)20-    7H  „  0.8756:1:0.9484 

III.  3MnO  •6UOi-9(CH,CO),0-    6  H!  „  0.6330:1:0.3942 
3CdO  -6U08-9(CH3CO)20-    6H  „  0.6289:1:0.3904 

IV.  3CaO  -6U08-9(CH3CO)20-    6H  „  0.9798:1:0.3865 

3SrO         -6U03-9(CH3CO)20-  6H       „  1:0.3887 

V.     3  (NH4)20  •  6  U03  •  9  (CH3CO)20  „  1  :  0.4708 

3  K2O         •  6  U03  •  9  (CH3CO)2O  „  1  :  1.2830 

3Ag2O       -6U03-9(CH3CO)20  „  1:1:5385 

The  results  of  crystallographic  investigations  of  these  urano- 
acetates  are  in  remarkable  agreement  with  the  S.H.P.  theory. 

The  theoretical  possibility  of  two  series  (A  and  B)  of  these  urano- 
acetates  is  confirmed  by  the  existence  of  two  series  of  compounds 

(III  and  IV)  with  6  H  and  with  a  different  a  :  b  :  c  ratio. 

If  the  series  I  and  II  are  compared  it  will  be  seen  that  on  the  loss 

of  5  H  the  c-axis  is  largely  increased,  being,  in  fact,  almost  doubled. 
A  specially  interesting  example  of  the  change  in  the  geometrical 
constants  effected  by  adding  or  subtracting  side-chains  is  found  in  the 
humite  series  studied  by  Penfield  and  Howe,  to  which  attention  has 
been  drawn  by  P.  Groth657,  who  assigns  to  them  the  folio  whig  structural 
formulae  : 

Prolektite        [SiO  J  Mg  [Mg(F.  OH)], 

Chondrodite     [Si04]2Mg3[Mg(F.  OH)]2 

Humite  [Si04]3Mg5[Mg(F.  OH)], 

Clinohumite     [SiOJ4Mg7[Mg(F.  OH)], 

From  the  composition  of  these  minerals  it  follows  that  each  member 
of  the  series  differs  from  the  previous  one  by  Si04Mg2.  The  addition 
of  this  group  always  effects  a  definite  change  in  the  c-axis  whilst  the 
parameter  a  :  b  remains  practically  unchanged. 

The  geometrical  constants  of  these  compounds  are  : 


Prolektite       Monocl.  prism.  1.0803 

Chondrodite          „  „  1.0863 

Humite  Rhomb,  bipyr.  1.0802 

Clinohumite   Monocl.  prism.  1.0803 


3  x  0.6287  90°  0' 

5  x  0.6289  90°  0' 
7  X  0.6291 

9  x  0.6288  90°  0' 


INFLUENCE  OF  SIDE-CHAINS  ON  CRYSTALLINE  FORM    307 

There  is  here  a  surprising  regularity  which  may  be  expressed  in  the 
form  of  a  "  law  "  :  the  c-axes  of  these  minerals  are  in  the  ratio  of 
3:5:7:9. 

According  to  the  S.H.P.  theory,  and  assuming  the  fluorine  to  be 
replaceable  by  OH,  the  formulae  of  these  compounds  are  : 

Prolektite  18  MgO  •  6  SiOa  •  6  H20 

Chondrodite  15  MgO  -  6  SiO2  •  3  H2O 

Humite  14  MgO  •  6  Si02  •  2  H2O 

Clinohumite  13  MgO  -  6  Si02  •  1 J  H20  (approx.) 

The  structural  formulae  of  these  compounds  will  then  be  : 
3°  1J°  1° 

A  A 

oo  po_/\_oo  QO_/\_OO       QO. 


Si 


•aq, 


00  00        '"*  00  00  *  00 

3  ==Z  3  ='=3  3  =!= 


"       ,.•«!• 


Si 


Si 


II  I!  II  II 

3°  1J°  1°  J° 

Prolektite.  Chondrodite.  Humite.  Clinohuniite. 

In  the  compounds  of  the  above  series,  the  addition  to  or  separation  of 
MgO  only  occurs  in  the  direction  of  the  c-axis.  It  is,  therefore,  clear 
why  only  the  c-axis  undergoes  a  regular  change,  the  ratio  a  :  b  re- 
maining practically  constant. 

Of  special  interest  are  the  topical  parameters  suggested  by  W. 
Muthmann763  and  F.  Becke764  for  comparing  the  chemical  and  crystallo- 
graphic  properties  of  substances.  These  topical  parameters  are  a 
combination  of  the  crystallographic  parameter  with  the  molecular 
volume  ;  they  are  derived  from  the  spatial  relations  of  the  substances 
concerned  and  show  the  relative  distances  of  the  molecules  from  each 
other. 

W.  Muthmann  has  determined  the  topical  axial  ratios  of  the 
following  salts,  to  which  he  assigns  the  formulae  : 

KH2P04 

(NH4)H2P04 

KH2As04 

NH4H2As04 

and  considers  that  the  OK-  or  ONH4-groups,  the  residual  0  atom  and 
the  OH-groups  are  attached  to  the  P  atoms  symmetrically  in  the  chief 
plane  of  symmetry. 

J.  H.  van't  HofF65  endeavoured  to  explain  the  data  obtained  by 
W.  Muthmann  by  means  of  the  following  structural  formula  : 

K 


HO— P— OH 
O 


308  CONSEQUENCES  OF  STEREO-HEXITE-PENTITE  THEORY 

in  which  the  vertical  line  represents  the  main  axis  c.  The  substitution 
of  NH4  for  K  increases  the  length  of  this  axis,  whilst  the  substitution 
of  As  for  P  effects  changes  in  the  dimension  in  every  direction.  This 
formula  of  van't  Hoff's  does  not  permit  the  data  obtained  by  Muth- 
mann  to  be  predicted,  nor  does  it  show  any  relationship  between 
analogous  phenomena. 

In  accordance  with  the  H.P.  theory,  Muthmann 's  formulae  should 
be  multiplied  by  6,  so  as  to  give  : 

A.  (KH2P04)6       =  3  K20  •  6  H20  •  3  P205 

B.  (NH4H2PO4)6  =  3  (MH4)20  •  6  H20  •  3  P2O6 

C.  (KH2As04)6      =  3  K20  •  6  H20  •  3  As205 

D.  (NH4H2As04)6  =  3  (NH4)20  •  6  H20  •  3  As205 

In  each  case  the  formula  represents  the  minimum  molecular  weights. 
The  structural  formulae  of  the  salts  should  be  as  follows :  R  represent- 
ing K  or  NH4,  the  bonds  with  dots  indicate  OK-groups  and  the  bonds 
without  dots  the  OH-groups. 


X 
\/ 


3  R20  •  6  H20  •  3  X205 

This  structural  formula  permits  the  following  predictions  to  be 
made  :  1.  The  space  between  the  molecules  must  increase  or  dimi- 
nish in  the  same  or  almost  the  same  proportion  in  all  directions  within 
the  crystal,  if  P  as  a  whole  is  replaced  in  the  ring  by  As  or,  conversely, 
As  by  P,  as  the  bond  between  the  vertical  and  the  horizontal  axes  is 
influenced  in  the  same  manner.  2.  The  space  between  the  molecules 
can  only  change  in  the  direction  of  a  single  axis,  viz.  the  vertical  or 
main  axis,  if,  in  a  phospho-  or  arseno-salt,  potassium  is  replaced  by 
ammonium  or  vice  versd,  as  these  atoms  are  attached  in  the  direction 
of  the  vertical  axis. 

It  is  remarkable  how  fully  the  investigations  of  Muthmann  confirm 
the  consequences  of  the  S.H.P.  theory. 

According  to  Muthmann  the  space  between  the  molecules  is 
increased  in  all  directions  in  the  crystal  in  almost  exact  proportion,  if 
the  phosphorus  in  the  phospho-salts  mentioned  above  is  replaced  by 
arsenic.  The  increase  is  practically  the  same  with  ammonium  and 
potassium,  but  if  the  potassium  atom  in  potassium  phosphate  or 
arsenate  is  replaced  by  an  ammonium  atom,  the  centres  of  gravity  of 
the  units  composing  the  crystal  become  more  widely  separated  solely  in 
the  direction  of  the  main  axis. 


STRUCTURAL  FORMULA  OF  BENZENE 


309 


The  Structural  Formula  of  Benzene  according  to  the  S.H.P.  Theory 

From  a  study  of  the  crystalline  form  of  the  benzene  derivatives, 
P.  Groth659  has  discovered  "  laws  "  which  are  reminiscent  of  the  humite, 
phosphate  and  arsenate  series  previously  described.  The  crystallo- 
graphic  investigation  of  a  series  of  benzene  derivatives  has  shown  that 
there  are  certain  atoms  and  atomic  groups  which  replace  hydrogen  in 
benzene  and  its  derivatives  whilst  only  slightly  altering  the  crystalline 
form,  so  that  the  form  of  the  new  substance  may  be  compared  with  the 
original  one.  The  change  is  of  such  a  nature  that,  e.g.  in  rhombic  sub- 
stances, the  ratio  of  two  parameters  (a :  b)  remains  almost  constant  (with 
the  small  difference  which  all  isomorphous  bodies  show,  as  is  the  case 
with  the  humite  series),  whilst  only  the  third  axis  —  the  c-axis  — 
undergoes  a  notable  change  in  value.  The  atomic  groups  OH  and  N02 
act  in  this  manner.  It  is  probable  that  the  substitution  of  a  hydrogen 
atom  by  these  groups  in  benzene  and  its  derivatives  occurs  in  the 
direction  of  the  c-axis .  An  energetic  reaction  accompanies  the  substitu- 
tion of  a  hydrogen  atom  in  benzene  and  its  derivatives  by  Cl,  Br  and 
CH3  which  systematically  changes  the  crystalline  system  into  a  less 
regular  one.  This  may  be  due  to  substitution  in  the  direction  of  the 
a-  or  6-axis  and  not  in  that  of  the  c-axis. 

A  large  number  of  other  examples  might  be  given  to  show  that  the 
addition  of  side-chains  to  (or  their  separation  from)  the  molecule  results 
in  a  change  in  the  geometrical  constants  of  crystalline  substances. 

In  connection  with  the  foregoing  arguments  a  few  words  respecting 
the  structure  of  benzene  according  to  the  S.H.P.  theory  are  of 
interest. 

The  structural  formula  of  benzene  *  deduced  from  the  S.H.P. 
theory  resembles  the  "  diagonal  formula  "  of  Glaus660,  viz.  : 


H  — C 


H  —  C 


C  — H 


C  — H 


but  one  fact  deserves  prominence  :  according  to  the  S.H.P.  theory 
the  six  hydrogen  atoms  in  benzene  do  not  all  behave  alike,  J  of  them 
(on  the  c-axis)  acting  differently  from  the  rest  (on  the  a-  and  6-axes). 
This  consequence  of  the  S.H.P.  theory  agrees  with  Groth's  discovery 

*  The  reader  who  wishes  to  refresh  his  memory  will  find  an  excellent  statement  of 
the  ordinary  theories  of  the  constitution  of  benzene  in  "  Organic  Chemistry,"  by  W.  H. 
Perkin  and  E.  Stanley  Kipping,  and  in  most  text-books  on  organic  chemistry. — A.  B.  S. 


S10  CONSEQUENCES  OF  STEREO-HEXITE-PENTITE  THEORY 

that  if  the  hydrogen  atoms  on  the  c-axis  are  substituted  only  these 
are  changed,  whereas  substitution  of  the  hydrogen  atoms  in  the  a-  and  b- 
axes  is  accompanied  by  a  notable  change  in  the  system  of  crystallisa- 
tion. If,  on  the  contrary,  all  the  hydrogen  atoms  in  benzene  are 
assumed  to  be  alike,  Groth's  discovery  becomes  inexplicable. 

There  is  a  more  direct  proof  that  one-third  of  the  hydrogen  or 
carbon  in  benzene  behaves  differently  from  the  rest  in  chemical 
reactions,  viz.  the  results  of  the  investigations  of  Stohmann661  and  his 
associates  on  the  heat  of  combustion  of  the  aromatic  compounds  and 
their  hydration  products.  These  showed  that  the  heat- values  change 
continually  in  the  decomposition  of  di-hydro  compounds,  whilst  the 
increase  in  energy  on  the  entrance  of  the  first  two  hydrogen  atoms  in 
the  benzene  ring  is  notably  greater  ;  i.e.  one-third  of  the  carbons  in 
benzene  behave  differently  from  the  rest. 

That  Kekule's  formula  for  benzene  needs  modification  is  also  clear 
from  the  following  :  Ladenburg662  was  the  first  to  point  out  that 
Kekule's  formula 

CH 


CH"'     .YJH 


CH 


v 

CH 


CH 


implies  the  existence  of  at  least  four  bi-substitution  products.663  Of 
these,  three  are  the  derivatives  at  the  points  (1,  2),  (1,  3)  and  (1,  4), 
including  the  assumed  symmetry  of  the  positions  (1,  3)  and  (1,  5). 
There  is  also  at  least  one  series  of  derivatives  in  the  position  (1,  6), 
as  this  position  is  notably  different  from  the  position  (1,  2)  on  account 
of  the  double  bond  between  the  carbon  atoms  in  the  position  (1,  6). 
Glaus664  therefore  suggested  the  following  formula  for  benzene  : 

CH 


CH 


\3 


CH 


CH 


He  argued  from  this  that  there  are  two  kinds  of  valencies  in  benzene, 
viz.  (a)  those  in  compounds  produced  from  the  periphery  of  the 
hexagon,  and  (b)  those  formed  from  the  diagonals  of  the  hexagon. 
From  this  structural  formula — which  resembles  that  suggested  for 
benzene  by  the  S.H.P.  theory — the  existence  of  only  three  di- 
substitution  products  of  benzene  is  explained,  and  this  number  is  that 
actually  found  by  experiment. 

Another  formula  which  represents  the  structural  formula  of  benzene 


STRUCTURAL  FORMULA  OF  BENZENE  811 

in  a  manner  very  similar  to  the  S.H.P.  theory  is  the  centric  formula 
devised  by  Armstrong665  and  v.  Baeyer666 : 

H 


H  — C 
H  — C 


C  — H 
C  — H 


which  is  really  a  modification  of  Claus'  formula.    Von  Baeyer  has  also 
proposed  a  centric  formula  with  spatial  representation. 
Ladenburg's  prism  formula 

H 


H  — C 
H  — C 


C  — H 
C  — H 


was  one  of  the  first  stereo-chemical  formulae  for  benzene.  Other  stereo- 
chemical  formulae  have  been  devised  by  R.  Meyer668,  Thomsen669, 
Sachse670,  Schmidt671,  Vaubel672,  Hermann673,  Diamant674,  etc. 

It  has  frequently  been  pointed  out  in  the  foregoing  pages  that  the 
bond  between  the  units  of  hexite  and  pentite  radicles  is  weakened  by 
the  addition  of  side-chains  (see  p.  216,  etc.).  From  this  it  follows 
that  benzene  and  its  derivatives  must  be  more  stable  than  hydro- 
benzene  and  the  hydro-derivatives  of  benzene.  This  consequence  of 
the  theory  is  confirmed  by  the  facts.  The  hydro-derivatives  of  benzene 
have  been  shown  by  the  investigations  of  v.  Baeyer  to  differ  consider- 
ably from  those  which  are  not  hydrated.  For  instance,  di-  and  tetra- 
hydro-derivatives  were  shown  to  have  a  marked  olefine  character. 
Thus,  phthalic  acid  is  completely  resistant  to  potassium  permanganate 
solution,  but  the  di-hydrophthalic  acids  are  oxidised  by  it.  The 
benzene  nucleus  is  not  sensitive  to  hydrobromic  acid  and  oxidising 
agents,  but  this  resistance  does  not  exist  in  the  hydro-benzenes. 

The  stability  of  benzene — which  has  been  proved  experimentally — 
is  in  direct  contradiction  to  Kekule's  formula.675 

That  a  close  relationship  exists  between  compounds  of  the  aliphatic 


312  CONSEQUENCES  OF  STEREO-HEXITE-PENTITE  THEORY 

and  aromatic  series  (c/.  p.  270),  as  may  be  inferred  from  the  S.H.P. 
theory,  has  been  proved  by  the  work  of  Schiff 676,  Lessen  and  Zander677, 
Horstmann678  and  Briihl679.  From  this  it  must  be  seen  that  the 
formation  of  hydro-derivatives  of  olefinic  and  aromatic  compounds  is 
analogous. 

D.  The  Optical  Properties  of  Crystals  and  the  S.H.P.  Theory 

The  physical  properties  of  crystals  are  well  known680  to  bear  a 
very  close  relationship  to  their  morphological  characters.  Light, 
heat  and  electricity  operate  in  complete  agreement  in  crystals,  and 
the  crystal  systems  arrange  themselves  in  the  same  manner.  This  may 
be  used  as  an  argument  in  favour  of  grouping  according  to  the  optical, 
thermic,  magnetic  and  other  properties  of  crystals.  Hence,  if  the 
optical  properties  of  a  crystal  are  known,  it  may  be  stated  that  each 
geometrical  plane  of  symmetry  of  a  crystal  is  also  a  physical  one  and 
that  two  crystallographic  equivalent  directions  have  also  a  physical 
relationship.* 

There  are,  however,  exceptions  to  this  rule  :  some  crystals,  for 
instance,  are  regular  and  their  physical  properties  indicate  no  isotropic 
construction.  In  this  connection  the  optical  characters  of  crystals 
are  frequently  curious.  An  interesting  example  of  this  is  found  in  the 
alum  crystals :  as  substances  which  crystallise  regularly  they  should  be 
optically  isotropic,  but  Brewster681  showed  in  1816  that  the  alums 
have  a  double  refraction.  Biot682,  who  has  still  further  studied  these 
characteristics  of  the  alums,  confirms  this  view;  The  double  refraction 
of  the  alums  has  also  been  studied  by  Reusch683,  E.  Mallard684,  F. 
Klocke685,  Brauns686  and  other  observers.  Several  explanations  have 
been  offered  to  account  for  their  abnormal  behaviour.  The  ordinary 
theory  of  crystalline  structure  neither  affords  an  explanation  nor  does 
it  give  anything  whereon  one  may  be  founded.  Mallard687  endeavoured 
to  explain  the  anomaly  crystallographically  by  assuming  a  special 
structure  of  the  alum  crystals,  and  regarded  them  as  consisting  of 
several  individuals  of  lower  symmetry  than  that  of  the  whole  crystal. 
Although  several  mineralogists  have  expressed  their  sympathy  with 
this  view,  others,  such  as  F.  Klocke688,  disagree  with  it.  Klocke 
considered  that  the  optical  anomalies  of  the  alums  are  due  to  a  "  state 
of  tension,"  but  he  regards  the  question  as  still  open. 

No  less  interesting  is  the  cause  of  the  rotation  of  the  plane  of 
polarised  light  shown  by  some  crystals ;  there  is  ample  reason  for  re- 
ferring this  to  the  chemical  constitution  of  the  crystals.  This  hypo- 

*  Von  Federow  has  recently  prepared  a  Table,  comprising  no  less  than  10,000 
substances,  the  crystals  of  which  have  been  adequately  measured  by  skilled  crystallo- 
graphers.  By  means  of  this  Table,  von  Federow  declares  it  is  possible  to  identify  any 
substance  included  in  it  when  the  crystals  have  been  properly  measured.  The  Table 
is  not  available  for  general  use,  but  in  the  hands  of  Prof.  Federow  it  has  proved  very 
successful.  A  brief  account  of  Federow's  theory  is  given  in  Tutton's  "  Crystallography 
and  Practical  Crystal  Measurement"  (Macmillan). — A.  B.  S. 


OPTICAL   PROPERTIES   OF  CRYSTALS 

thesis  is  confirmed  by  the  enantiomorphism  of  the  circular  polarising 
substances. 

[Enantiomorphous  crystals  are  those  which  have  the  same  relation  to  each  other 
as  an  object  has  to  its  mirror-image,  as  will  be  seen  by  holding  the  sketch  of  crystal  I 
before  a  mirror,  when  the  darkened  faces,  a,  6,  will  appear  as  in  the  sketch  in  crystal  II 
viewed  directly,  and  vice  versa.} 


I.  U. 

Enantiomorphous  Crystals. 

As  early  as  1848,  Pasteur689,  in  studying  optically  active  tartaric  acid 
and  the  optically  inactive  racemic  acid,  discovered  this  relationship 
between  crystalline  form  and  optical  activity.  Groth  also  regards 
optical  activity  as  entirely  due  to  the  structure  of  the  smallest  particles 
of  circular  polarising  crystals.  He  considers  that  if  this  optical 
property  is  characteristic  of  the  crystal  molecule  itself,  the  solution 
must  be  saturated  in  order  to  produce  optical  rotation;  as,  unless  the 
particles  in  solution  have  a  complexity  comparable  to  that  of  the 
crystalline  molecules,  no  separation  of  the  substance  in  a  crystalline 
state  can  possibly  occur.  With  many  substances,  however,  this  is  not 
the  case  ;  for  instance,  solutions  of  sodium  chlorate  show  no  optical 
rotation,  but  only  those  crystals  whose  forms  are  such  that  they  are 
mirror-images  of  each  other. 

An  apparently  complete  proof  of  this  view  is  found  in  the  interesting 
observation  of  Reusch690  on  the  production  of  circular  polarisation  in 
mica  plates.  According  to  Reusch,  if  a  large  number  (12-36)  of 
uniform  thin  plates  of  bi-axial  mica  are  laid  one  above  another  so  that 
the  plane  of  the  (vertical)  optical  axis  of  each  plate  is  turned  to  the 
right  through  an  angle  of  120°  with  respect  to  the  plate  below  it,  this 
combination  of  plates  turns  the  plane  of  polarisation  of  a  vertical 
beam  of  light  to  the  right,  the  combination  behaving,  in  a  polarisation 
apparatus,  in  a  manner  similar  to  a  plate  of  dextro-rotatory  quartz  cut 
vertically  to  the  axis.  If  the  mica  plates  are  turned  through  an  angle 
of  120°  in  the  opposite  direction,  the  combination  is  laevo-rotatory. 

Pasteur's  discovery  respecting  the  crystalline  forms  of  optically 
active  tartaric  acid  and  the  inactive  racemic  acid,  the  fact  that  some 
substances  only  show  circular  polarisation  effects  when  in  the  solid 
state,  and  the  property  of  the  mica  sheets  discovered  by  Reusch,  all 
show  that  there  is  undoubtedly  a  relationship  existing  between  optical 
activity  and  the  structure  of  crystals,  though  it  has  not  yet  been 
proved  that  optical  activity  is  entirely  produced  by  the  peculiar  struc- 


314  CONSEQUENCES  OF  STEREO-HEXITE-PENTITE  THEORY 

ture  of  such  crystals.  The  fact,  pointed  out  by  Groth,  that  some 
substances  only  rotate  the  plane  of  polarisation  when  in  the  solid 
form,  is  not  a  complete  proof,  as  on  entering  into  solution  equivalent 
amounts  of  laevo-  and  dextro-rotatory  substances  may  be  formed  and 
so  make  the  solution  inactive.  As  a  matter  of  fact,  Groth  has  found 
that  a  solution  of  NaC103  in  which  laevo-  and  dextro-rotatory  crystals 
of  this  substance  are  dissolved,  can  deposit  both  laevo-  and  dextro- 
rotatory crystals. 

If  the  optical  activity  is  entirely  conditioned  by  the  peculiar  crystal- 
line form  of  some  substances,  enantiomorphous  crystals,  such  as  the 
regular  tetrahedric  or  trapezoidal  hemihedric  substances,  should 
necessarily  have  the  power  of  circular  polarisation.  This  is  not  the 
case.  For  instance,  L.  Wulff691  has  shown  that  lead,  barium  and 
strontium  nitrates,  in  spite  of  the  regular  tetrahedric  form  of  their 
crystals,  i.e.  their  enantiomorphous  constitution,  have  no  effect  on 
the  plane  of  polarisation  either  in  the  solid  or  dissolved  state.  A 
further  series  of  substances  whose  crystalline  form  is  that  of  the 
trapezoidal  hemihedric  substances  did  not  show  any  optical  activity 
when  examined  by  WulfL  This  fact  implies  that  the  cause  of  the 
property  of  circular  polarisation  must  be  dependent  on  the  chemical 
constitution  of  the  crystal  nuclei,  quite  apart  from  the  physical 
structure  of  the  crystal ;  optically  active  substances  must  not  only  be 
enantiomorphous,  but  must  have  a  definite  chemical  structure.  For 
instance,  lead,  barium  and  strontium  nitrates  are  truly  enantiomor- 
phous, but  they  do  not  possess  the  structure  of  optically  active  sub- 
stances and  they  are,  therefore,  optically  inactive.  Hence  it  is  neces- 
sary to  enquire  what  chemical  structure  is  essential  to  render  enantio- 
morphous substances  optically  active. 

It  is  probable  that  the  optical  anomalies  of  some  regularly  crystal- 
lisable  substances  are  of  a  constitutional  nature,  and  if  the  chemical 
factors,  such  as  those  which  cause  the  optical  abnormalities  of  the 
alums,  could  be  discovered,  it  is  not  improbable  that  these  factors 
would  be  the  causes  of  circular  polarisation. 

The  following  facts  show  that  chemical  structure  has  an  undoubted 
influence  on  the  optical  properties  of  crystals  : 

Mallard,  in  his  studies  of  the  zeolites,  has  observed  that,  on  pro- 
longed heating,  these  slowly  change  their  optical  properties  in  con- 
sequence of  the  steady  loss  of  their  water  of  crystallisation,  i.e.  by 
changes  in  the  side-chains,  until  finally  the  crystal  has  the  properties 
of  the  anhydrous  substance.  This  condition  continues  if  a  re- 
absorption  of  water  is  prevented,  as  by  embedding  in  Canada  balsam ; 
but  if  the  temperature  reached  has  not  been  excessive  and  the  crystal 
is  allowed  to  cool  in  moist  air  it  will  regain  its  water  almost  completely, 
and,  simultaneously  with  this,  its  optical  properties.  In  this  way 
Mallard  has  found  a  direct  proof  for  the  dependence  of  the  optical 
characters  on  the  chemical  constitution. 

In  the  case  of  circularising  substances,  it  is  noteworthy  that  Le 


OPTICAL  PROPERTIES  OF  CRYSTALS  315 

Bel692  and  van't  Hoff693  discovered,  almost  simultaneously,  the  fact 
that  all  organic  compounds  which  rotate  the  plane  of  polarisation  of 
light  contain  asymmetric  carbon  atoms,  i.e.  carbon  atoms  in  which 
each  of  the  four  valencies  is  saturated  with  a  different  group  of  atoms. 
As  it  has  been  observed  that  all  organic  substances  which  are  optically 
active  contain  one  or  more  asymmetric  carbon  atoms,  it  appears 
probable  that  the  source  of  optical  anomalies  and  of  circular  polarisa- 
tion may  be  due  to  this  asymmetry  or  to  an  asymmetrical  substitution 
of  the  side-chains  or  of  the  hexite  and  pentite  in  some  substances. 
From  this  it  follows  that  a  potash  alum  of  the  structural  formula 

-A  A/ 

=  I  S  I  Al  I  S 


3  K20  •  12  H20  -  3  A120,  •  12  SO,  •  10  H 

will  have  a  normal  optical  behaviour,  i.e.  it  must  be  isotropic.  If, 
however,  part  of  the  potassium  is  replaced  by  sodium,  lithium  or  a 
similar  metal,  or  if  part  of  the  aluminium  is  replaced  by  Fe'",  Cr"', 
Mn'",  etc.,  or  if  part  of  the  sulphur  is  replaced  asymmetrically  by 
selenium,  the  crystalline  form  remaining  unchanged,  i.e.  regular,  these 
substances  will  be  optically  aniso tropic. 

In  an  analogous  manner  the  source  of  circular  polarisation  may  be 
considered  as  due  to  the  chemical  structure  of  enantiomorphous 
substances. 

It  is  not  surprising  that  Brauns694  has  shown  experimentally  that, 
as  a  matter  of  fact,  the  pure  alums  are  optically  isotropic,  but  the 
mixed  ones  are  double  refracting,  i.e.  anisotropic.  According  to 
Brauns,  all  crystals  of  pure  potash-alumina-alum  and  ammonia- 
alumina-alum  are  optically  isotropic,  but  those  crystals  which  are 
produced  from  solutions  of  the  mixed  substances  are  optically  different 
and  show  a  double  refraction.  Crystals  obtained  from  a  solution 
containing  equal  weights  of  ammonia-  and  potash-alum  show,  according 
to  Brauns,  a  very  strong  double  refraction,  are  full  of  irregular  cracks, 
and,  on  removing  them  from  the  solution,  they  fall  to  pieces.  On 
representing  the  structure  of  such  an  alum  by 


the  NH4-groups  being  marked  +  and  the  potassium  atoms  •  its 
asymmetric  structure  is  clear  and  the  abnormal  optical  behaviour 
of  this  alum,  the  irregular  cracks  in  it,  and  the  falling  to  pieces  of  the 
crystals  on  removing  them  from  the  solution  are  rendered  explicable. 


316  CONSEQUENCES  OF  STEREO-HEXITE-PENTITE  THEORY 

It  is  noteworthy  that  Brauns  has  observed  faint  circular  polarisa- 
tion phenomena,  in  consequence  of  which  it  is  highly  probable  that 
such  asymmetric  substitution  is  the  cause  of  the  optical  activity  of  a 
number  of  enantiomorphous  substances.  As  a  matter  of  fact,  the 
micas  from  which  Reusch  built  his  optically  active  compounds  are 
silicates  in  which  both  the  side-chains  and  the  aluminium  hexites  and 
pentites  are  composed  of  different  constituents  which  are  often 
asymmetrically  arranged  in  the  molecule  (see  "  Micas  "  in  Appendix). 

Some  substances,  such  as  quartz,  are  optically  active  and,  without 
exception,  possess  enantiomorphous  crystalline  forms.  Their  structural 
formulae,  as  derived  from  ultimate  analyses  and  other  studies,  must  be 
asymmetric  if  this  theory  of  circular  polarisation  is  correct  and  of 
general  application. 

The  Bravais-Frankenheim  theory  of  crystalline  structure  does  not 
indicate  the  enantiomorphous  forms.  Sohncke  sought  for  the  source 
of  optical  rotation  of  some  crystals  and  of  the  appearance  of  these  in 
enantiomorphous  forms  in  an  inner  structure  of  the  same,  which  is 
similar  to  Reusch  Js  mica  arrangement.  The  theory  of  crystalline 
structure  may  be  enlarged  in  this  direction.  The  optically  active 
crystals  consist,  according  to  him,  of  step-like  lamellae  which  are 
optically  bi-axial  and  do  not  show  double  refraction  in  the  axis  of 
rotation,  but  show  circular  polarisation  effects. 

The  S.H.P.  theory  may  also  be  enlarged  in  the  same  sense.  The 
units  may  be  so  arranged  that  a  series  of  double  pyramids  (see  P  and 
P',  pp.  286  and  287)  P,  P',  P",  P'"  .  .  .  with  the  surfaces  ABDE, 
A'B'D'E',  A"B"D"E"  ...  are  produced.  These  double  pyramids 
P,  P',  P"  .  .  .  have  axes  AD,  ATX,  A"  D"  .  .  .  BE,  B'E',  B"E"  .  .  . 
arid  are  so  placed  that  each  of  their  axes  in  the  base  forms  an  angle  of 
120°  in  the  direction  of  the  movement  of  the  hands  of  a  clock,  or 
vice  versa  with  the  corresponding  axes  of  the  next  base,  i.e.  AD  with 
A'D',  A'D'  with  A"D",  A"D"  with  A'"D'".  In  the  first  case  dextro-, 
and  in  the  second  laevo-rotatory  crystals  are  produced,  provided  that 
the  crystals  are  also  chemically  asymmetric. 

The  S.H.P.  theory  thus  provides  a  single  explanation  for  the  cause 
of  circular  polarisation  in  both  organic  and  inorganic  compounds. 

E.   The  Dependence  of  the  Geometrical  Constants  on  the  Temperature 

The  bonds  between  the  nuclei  of  the  radicles  (i.e.  the  hexites  and 
pentites)  and  between  the  radicles  and  the  side-chains  are  loosened  by 
the  addition  of  bases,  water  of  constitution  and  of  crystallisation  and 
on  raising  the  temperature.  Hence,  on  altering  the  temperature  the 
geometric  constants  must  be  influenced,  as  they  have  a  close  relation- 
ship to  the  valency-forces.  The  consequence  of  the  theory  is  also 
confirmed  by  the  facts. 

Mitscherlich695,  G.  Rose696,  F.  de  Filippi697,  Frankenheim698  and 
others  have  shown  that  when  aragonite  is  heated  to  a  suitable 


MOLECULAR  VOLUMES 


317 


temperature  it  is  converted  into  calcspar.  Hauy699  has  also  observed 
that  on  heating  aragonite  to  a  dull  red  heat  it  falls  to  powder,  and 
Haidinger700  represented  this  process  as  a  conversion  of  aragonite 
into  calcspar.  G.  Rose701  has  shown  that  calcite  and  also  aragonite  are 
formed  from  warm  solutions  of  CaC03  and  that,  at  higher  temperatures, 
only  calcite  is  formed.  C.  Klein702  has  made  the  interesting  observa- 
tion that  a  plate  cut  from  aragonite  in  a  direction  vertical  to  the 
principal  axis  becomes  optically  monoaxial  and  has  a  negative  double 
refraction  when  heated,  i.e.  the  plate  assumes  the  characteristic 
properties  of  calcspar  when  warmed. 

The  changes  of  the  crystalline  forms  of  substances  on  raising  their 
temperature  has  been  observed  in  numerous  cases  by  O.  Lehmann703, 
who  has  examined  two  groups  of  polymerised  substances,  of  which : 

1.  The  members  of  one  group  are  converted,  with  absorption  of 
heat,  into  another  modification  ;     on  cooling,  the  original  form  (en- 
antio tropic  modification)  is  reproduced  and  heat  is  evolved. 

2.  The  members  of  the  other  group  are  stable  and  labile  modifica- 
tions which  differ  from  the  enantiotropic  substances  and  are  not 
converted  into  other  forms  on  alteration  of  the  temperature. 


F.   Molecular  Volumes  and  the  S.H.P.  Theory 

It  follows  from  the  S.H.P.  theory  that  the  molecular  volumes  of 
analogously  constituted  substances  cannot  be  identical,  as  the  affinities 
between  the  various  nuclei  must  differ  from  each  other. 

An  interesting  confirmation  of  this  consequence  of  the  theory  is 
found  in  the  results  of  investigations  of  the  molecular  volumes  of  a 
series  of  alums  by  O.  Petterson704,  which  are  shown  in  the  following 
Table  : 


Sulphate  Alums 

Mol. 
Vols. 

Selenate  Alums 

Mol. 
Vols. 

Differ, 
between 
Vols. 

KiH«4(S-Al-§.) 

10  H 

541.6 

K«6H°24(Se-Al-Se) 

10  H 

568.0 

26.4 

(NH4)OHJ4(S-A1-S)       - 

10  H 

552.2 

(NH4)«H°4(Se-Al-Se)    • 

10  H 

578.6 

26.4 

Rb°8H°4(S-Al-S) 

10  H 

551.0 

Rb<jH|j4(Se-Al-Se) 

10  H 

576.2 

25.2 

Cs6°H°4(S-Al.S) 

10  H 

569.2 

Cs°6H°4(Se-Al-Se) 

10  H 

595.6 

26.4 

Kj>H°24(S-(>S) 

10  H 

542.2 

K«H024(Se-Al-Se) 

10  H 

571.0 

28.8 

(NH4)°6H|4(S-Cr-S)       • 
RbgH°4(S-Cr-S) 

10  H 
10  & 

553.6 
554.6 

(NH4)°6Ho4(Se-Al.Se)  • 
Rb«H°4(Se-Al-Se) 

10  Bt 
10  H 

577.4 
576.8 

23.8 
22.2 

T1°H°24(S-(>S) 

10  H 

554.2 

Tl»H2°4(Se-Al-Se)         r 

10  H 

576.6 

22.4 

From  this  Table  it  may  be  seen  that  not  only  are  the  molecular 
volumes  of  different  alums  not  identical,  but  that  there  is  a  striking 
regularity  in  the  difference  in  the  molecular  volumes  caused  by  the 
substitution  of  selenium  for  sulphur. 


Summary  and  Conclusions 

IN  the  foregoing  pages  an  attempt  has  been  made  to  obtain  a  glance  at 
the  structure  of  the  silicon  compounds .  After  a  critical  examination 
of  existing  theories  which  have  been  proposed  for  the  representation  of 
the  structure  of  the  aluminosilicates  and  the  silicates  generally,  it  has 
been  found  that  the  conception  of  the  aluminosilicates  as  complex 
acids  or  salts  of  complex  acids  agrees  best  with  the  facts.  The 
reactions  of  the  aluminosilicates  can  only  be  understood  if  both 
alumina  and  silica  are  regarded  as  playing  similar  roles  in  the  silicates, 
i.e.  the  roles  of  acids.  A  number  of  properties  appear,  however,  to 
contradict  the  theory  of  the  aluminosilicates  as  complex  compounds, 
and  this  conception  does  not  enable  any  systematic  arrangement  to 
be  made  of  all  the  aluminosilicates  in  spite  of  the  undoubted  genetic 
relationship  between  them. 

It  is  very  surprising  that  scarcely  any  of  the  critics  of  the  German 
edition  of  this  work  have  paid  any  attention  to  the  main  thesis  that 
the  silicates,  or  more  correctly  the  aluminosilicates,  should  be  classed 
with  the  complex  acids.  Yet  it  is  stated  quite  definitely  on  page  30  : 
"  It  is,  however,  not  improbable  that  these  objections  (i.e.  to  the  sixth 
hypothesis)  are  only  apparent,  and  that  they  would  be  completely 
overcome  if  the  manner  in  which  the  atoms  in  the  anhydrides  of  the 
aluminosilicates  are  bound  to  each  other  were  known.  By  the  use  of  a 
suitable  hypothesis  for  the  structure  of  these  anhydrides  a  confirmation 
of  this  statement  may  be  found.  The  authors  of  this  present  volume 
have  actually  formulated  such  a  hypothesis,  and  its  nature  and  the 
conclusions  to  be  drawn  from  it  form  the  subject-matter  of  the  following 
pages." 

On  page  62  it  is  stated  that:  "The  conclusion  has  already  (see  pp. 
22  and  26)  been  reached  that,  of  all  the  theories  devised  for  showing 
the  constitution  of  the  aluminosilicates,  the  one  which  agrees  best 
with  the  facts  is  that  which  assumes  that  these  compounds  are  complex 
acids  and  the  corresponding  salts." 

On  page  63  it  is  stated  that :  "The  conception  of  the  alumino- 
silicates as  complex  acids  thus  agrees  excellently  with  the  experi- 
mental results." 

On  pages  79-102  it  is  shown  that  the  molybdenum  and  tungsten 
complexes,  i.e.  the  complex  acids  and  their  salts,  are  par  excellence  true 
analogues  of  the  aluminosilicates  and  agree  perfectly  with  structural 
formulae  which  are  fully  analogous  to  those  used  for  the  alumino- 
silicates. 

318 


SUMMARY  319 

The  foregoing  quotations,  and  the  present  work  as  a  whole,  show 
clearly  that,  quite  apart  from  the  hexite-pentite  theory,  the  view  that 
aluminosilicates  are  complex  acids  and  salts  is  the  foundation  on  which 
a  knowledge  of  the  constitution  of  these  substances  must  be  based. 
Yet  this  fact,  as  already  remarked,  does  not  appear  to  have  been 
noticed  by  a  single  critic.  Thus,  in  a  review  by  J.  J.  P.766  it  is  stated 
that :  "The  conception  of  hexite  and  pentite  radicles  (ring-compounds 
with  5  or  6  Al-  or  Si-atoms  and  a  number  of  0-atoms)  is  the  foundation 
of  a  systematic  study  of  the  silicates." 

Stremme767  commences  with  the  view  that  the  hexite-pentite 
theory  is  the  sole  foundation  of  the  present  volume,  and  then  reaches 
the  remarkable  conclusion  that  the  chief  difficulty  in  mineral  chemistry 
— the  explanation  of  the  extraordinarily  great  variations  in  the  com- 
position of  the  silicates — becomes  "  playfully  easy,"  "it  is  only 
necessary  to  introduce  new  hexite  and  pentite  groups  into  existing 
combinations."  He  then  stated  that :  "  In  not  a  single  case  is  it  shown 
that  even  one  silicate  must  necessarily  contain  a  hexite  or  pentite 
group." 

In  reply  to  this  criticism,  which  completely  overlooks  the  complex 
nature  of  the  aluminosilicates,  it  may  be  well  to  remark  that  the  H.P. 
structural  formulae  of  the  aluminosilicates  have  been  devised  in 
accordance  with  definite  rules,  and  in  no  case  have  "  new  hexites  or 
pentites  "  been  introduced  in  a  haphazard  manner.  The  proof  that 
the  aluminosilicates  have  the  constitution  indicated  by  the  H.P. 
theory  (i.e.  that  they  contain  hexites  or  pentites  of  silicon  and 
aluminium  which  are  arranged  in  accordance  with  definite  laws)  has 
been  published  in  the  customary  scientific  manner,  as  everyone  who  will 
read  it  impartially  must  admit.  The  theoretically  possible  formulae 
were  first  set  down,  and  the  consequences  deducible  from  them  were 
then  compared  with  the  available  experimental  evidence.  Stremme 
terms  this  "  not  proved,"  and  his  contention  might  be  sound  if  the 
experimental  evidence  did  not  agree  with  the  logical  conclusions  from 
the  theory.  As  a  matter  of  fact,  the  agreement  is  remarkably  close. 
If  Stremme  or  any  other  critic  can  find  a  better  method  of  testing  a 
theory  than  the  one  adopted  in  the  present  volume,  he  would  render 
an  inestimable  service  to  mankind  if  he  would  publish  it. 

The  method  adopted  by  this  critic  to  show  the  "  worthlessness  " 
of  the  H.P.  theory  could  be  easily  used  to  upset  the  most  firmly- 
established  theories.  For  example,  on  what  foundations  are  the  atomic 
theory,  the  benzene  theory  and  the  theory  of  dissociation  based  ? 
Surely  they  have  been  accepted  as  the  result  of  entirely  analogous 
methods  of  argument  to  those  used  in  the  present  volume  ! 

C.  H.  Desch736  has  overlooked  the  fact  that  the  main  foundation  of 
this  exposition  of  the  constitution  of  aluminosilicates  is  the  fact  of 
their  complex  nature,  inasmuch  as  he  states  that  "  the  felspars,  the 
hardening  of  cements,  the  hydra tion  of  zeolites  .  .  .  are  dealt  with 
exclusively  from  a  structural  chemical  point  of  view." 


320  SUMMARY 

A  further  criticism  of  Desch's  views  will  be  found  on  reference  to 
the  Name  Index. 

Allen  and  Shepherd737  also  appear  to  have  completely  overlooked 
the  fact  that  the  complex  nature  of  the  aluminosilicates  is  the  essential 
basis  of  the  constitution  attributed  to  them  by  the  authors  of  the  H.P. 
theory,. and  it  appears  strange  to  them  that  the  structure  of  the  complex 
compounds  of  tungsten,  vanadium  and  molybdenum  should  also  be 
described  in  the  present  volume.  It  is,  nevertheless,  very  remarkable 
that  Allen  and  Shepherd  have  overlooked  this  fact,  or  even  that  they 
could  overlook  it,  as  they  specifically  refer  to  "an  excellent  review  of 
previous  theories  of  the  structure  of  silicates  and  a  proof  of  their 
insufficiency  "  contained  in  the  present  work.  Yet  in  this  review  it 
is  clearly  shown  that  the  starting  point  of  any  theory  of  alumino- 
silicates must  be  based  on  their  complex  nature.  It  is  the  neglect  of 
this  which  leads  Allen  and  Shepherd  to  oppose  the  application  of 
the  new  theory  to  Portland  cements.  If  they  had  only  seen  that  the 
aluminosilicates  are  complex  acids  or  the  corresponding  salts,  they 
must  have  realised  the  a  priori  probability  of  the  existence  of  highly 
basic  calcium  aluminosilicates,  i.e.  they  must  have  reached  a  concep- 
tion of  the  constitution  of  Portland  cements  which  agrees  with  the  one 
herein  published.  If  a  theory  shows  the  possible  existence  of  these 
substances,  and  all  their  properties  agree  with  the  structural  formulae 
which  are  based  on  the  theory,  there  is  no  reason  to  doubt  the  correct- 
ness of  the  constitutions  thus  formulated. 

Manchot775,  alone  of  all  the  critics,  refers  to  the  complex  nature  of 
the  aluminosilicates.  From  his  statement — "It  is  in  any  case  worth 
consideration  whether  it  can  be  proved  that  among  the  silicates  as  in 
other  branches  of  chemistry  the  number  6  plays  so  special  a  part " — 
it  follows  that  he  considers  that  the  new  theory  cannot  in  any  way  be 
regarded  as  properly  supported  by  facts.  This  critic  should,  however, 
state,  at  the  earliest  opportunity,  how  large  must  be  the  mass  of  facts 
in  support  of  a  theory  before  he  would  consider  that  theory  established. 
If  his  attitude  in  his  own  researches  may  be  regarded  as  satisfactory 
to  himself,  he  will  doubtless  be  interested  to  refer  to  an  investigation  he 
made  in  1905  into  the  constitution  of  silicides  and  published  in  the 
"Annalen  der  Chemie,"  1905,  3J$,  356-363.  In  this  instance  this 
investigator  did  not  hesitate  to  state  that  these  compounds  form 
hexites,  notwithstanding  that  he  had  only  a  single  fact  upon  which  to 
rely  for  his  conclusion,  viz.  the  behaviour  of  these  substances  towards 
hydrofluoric  acid.  Yet  when  he  comes  to  review  the  German  edition 
of  the  present  work,  he  considers  that  the  innumerable  facts  and  the 
whole  mass  of  available  experimental  evidence  are  not  sufficient  to 
establish  the  hexite  formation  of  the  silicates  !  The  number  and 
importance  of  these  facts  and  the  manner  in  which  this  critic  uses  his 
own  experimental  results  in  criticising  the  constitutional  formulae  of 
the  silicates — quietly  passing  over  in  silence  those  which  may  happen  to 
agree  with  the  theory  he  is  criticising — is  highly  significant  (see  p.  273). 


SUMMARY  321 

The  H.P.  theory  is  the  first  one  enabling  structural  formulae  to  be 
devised  in  agreement  with  the  conception  of  the  aluminosilicates  as 
complex  compounds,  which  is  free  from  the  drawbacks  of  the 
earlier  theories,  is  capable  of  being  used  in  the  systematic  arrange- 
ment of  all  the  silicates  and  also  enables  a  series  of  properties 
of  the  aluminosilicates  to  be  predicted  a  priori,  which  have,  so 
far  as  they  have  been  investigated  experimentally,  been  fully  con- 
firmed. 

Thus  the  structural  formulae  of  the  silicates  devised  by  means  of 
the  H.P.  theory  have  led  to  the  remarkable  prediction  that  all  the 
aluminium  and  silicon  atoms  in  the  aluminosilicates  will  not  behave 
exactly  alike  when  examined  chemically  and  physio-chemically,  and 
that  atoms  occupying  certain  positions  in  the  molecule  will  behave 
differently  from  the  rest.  This  consequence  of  the  theory  is  fully 
confirmed  by  the  available  experimental  material,  and  particularly 
by  the  work  of  Thugutt,  Silber  and  others. 

The  agreement  between  the  minimum  molecular  weights  which 
may  be  inferred  from  the  H.P.  theory  and  those  found  experimentally 
is  also  important,  particularly  as  regards  the  results  obtained  by 
Thugutt  on  a  series  of  aluminosilicates  such  as  orthoclase,  nepheline, 
and  the  sodalites. 

Considerable  importance  also  attaches  to  that  consequence  of  the 
H.P.  theory  which  states  that  chemical  compounds  may  contain 
various  kinds  of  combined  water — "  water  of  constitution  "  and 
"  water  of  crystallisation  " — the  first  being  acid- water  and  the  second 
basic-water,  and  to  the  agreement  of  this  consequence  with  the 
facts  ascertained  experimentally — such  as  Clarke's  studies  of  the 
zeolites. 

The  H.P.  theory  is  not  only  applicable  to  the  representation  of  the 
structure  of  the  aluminosilicates,  but  to  the  complex  acids  generally. 
According  to  the  investigations  of  Gibbs,  Blomstrand,  Pechard, 
Parmentier,  Kehrmann,  Friedheim  and  others,  complex  acids  are 
produced  by  the  union  of  one  acid  with  another,  e.g.  of  molybdic 
acid  with  vanadic,  phosphoric,  antimonic  or  arsenic  acid;  and  of 
aluminic  acid  with  phosphoric,  vanadic,  molybdic,  sulphuric  or 
tungstic  acid.  By  means  of  the  H.P.  theory  the  structure  of  all  the 
various  complex  acids  and  their  salts  can  be  shown  on  a  priori  grounds. 
This  theory  also  shows  that  a  genetic  relationship  must  exist  between 
the  various  complex  acids  of  the  same  class,  e.g.  between  all  the 
aluminosilicates,  all  the  aluminophosphates,  all  the  aluminosulphates, 
and  between  all  the  salts  of  the  complex  acids  of  the  same  class.  As  a 
matter  of  fact,  such  a  relationship  does  exist,  as  may  be  seen  on 
examination  of  the  available  experimental  results. 

It  is  specially  important  to  observe  the  fact  that  the  addition  of  a 
basic  or  other  side-chain  weakens  the  bonds  of  the  nucleus,  and  that 
the  most  stable  types  of  the  complex  acids  are  those  in  which  the  ratio 
of  the  acid-forming  atoms  is  1 : 1 ;  thus,  the  most  stable  aluminosilicates 


322  SUMMARY 

are  those  with  a  ratio  of  A1203 :  Si02=l  :  2 ;  the  most  stable  vanado- 
tungstates  are  those  in  which  V205  :  WO3=1  :  2. 

The  H.P.  theory  is  also  of  value  in  ascertaining  the  constitution  of 
several  aluminosilicates  of  great  technical  importance,  such  as  clays, 
ultramarines,  Portland  cements,  slag  cements,  porcelain  cements,  etc. 
The  clays  are  of  great  technical  value  because  they  are  a  raw  material 
used  in  the  production  of  pottery,  cement,  ultramarines,  etc.,  and 
they  are  also  of  great  theoretical  importance  because  they  constitute 
some  of  the  various  aluminosilicic  acids  whose  existence  may  be  inferred 
from  the  H.P.  theory.  The  behaviour  of  clays  towards  strong  acids 
(the  so-called  "  rational  analysis  "),  the  cause  of  the  plasticity  of  clays 
and  the  changes  which  occur  on  burning  may  all  be  explained  by 
means  of  the  H.P.  theory.  Innumerable  investigations  have  been 
made  in  order  to  ascertain  the  constitution  of  the  ultramarines.  The 
H.P.  theory  supplies  a  hypothesis  from  which  the  structure  of  the 
whole  of  the  theoretically  possible  substances  of  the  ultramarine  class 
may  be  derived  ;  a  large  number  of  these  compounds  are  already 
known  to  exist.  On  the  other  hand,  no  ultramarines  have  yet  been 
found  which,  according  to  the  theory,  are  theoretically  impossible 
(such  as  those  in  which  A1203 :  Si02=  1:6).  The  ultramarine  theory, 
based  on  the  more  general  H.P.  theory,  is  in  entire  agreement  with  the 
experimental  results  of  the  valuable  work  of  Hoffmann,  Heumann, 
Philipp,  Szilasi,  Gmelin  and  others.  The  experimental  work  of 
Guckelberger  on  the  minimum  molecular  weight  of  some  ultra- 
marines is  in  remarkable  agreement  with  the  H.P.  theory  and  is  fully 
confirmatory  of  the  theoretical  inferences  from  it. 

Innumerable  attempts  have  also  been  made  to  ascertain  the 
structure  of  Portland,  slag,  porcelain  and  other  silicate  cements  and 
especially  to  explain  the  reactions  which  occur  during  the  hardening 
of  these  cements.  These  and  other  problems  find  a  clear  and  simple 
solution  when  once  the  structure  of  the  silicates  has  been  ascertained 
by  means  of  a  suitable  theory.  As  a  matter  of  fact,  the  H.P. 
theory  has  led  to  conceptions  of  the  structure  of  cements  which 
not  only  agree  with  experimental  observations,  but  also  permit 
of  very  full  prognostications  in  regard  to  the  possibility  of  solving 
the  great  problem  of  the  use  of  cement  in  sea-water  and  coastal 
masonry. 

The  new  H.P.  theory  has  proved  to  be  of  special  value  in  ascertain- 
ing the  structure  of  the  porcelain  (dental)  cements,  i.e.  those  compounds 
which  are  both  theoretically  and  practically  important  on  account  of 
their  extended  use  in  dentistry. 

The  poisonous  action  of  some  of  these  cements  has  been  studied, 
and  the  H.P.  theory  shows  which  portion  of  these  cements  has  a  toxic 
action  and  it  indicates  how  their  poisonous  nature  may  be  destroyed 
and  the  cements  rendered  quite  harmless.  To  solve  this  obviously 
physiological  chemical  problem  it  is  necessary  to  study  the  toxines 
generally  in  order  to  ascertain  the  nature  of  their  actions  and  the 


SUMMARY  323 

causes  of  the  poisoning.  Ehrlich's  theory  of  the  toxines  on  the  one 
hand  and  the  H.P.  theory  on  the  other  combine  to  solve  the  problem 
of  the  poisonous  nature  of  many  porcelain  cements  and  show  clearly 
which  of  the  available  cements  are  toxic,  or  at  least  risky,  and  which 
are  harmless. 

The  aluminosilicates,  generally  speaking,  cannot  be  satisfactorily 
studied  because  of  their  great  resistance  to  reagents,  few  of  the  ordinary 
methods  of  investigation  being  available.  Yet,  by  means  of  the  H.P. 
theory,  it  is  possible  to  produce  a  theory  of  such  general  application 
that,  with  the  aid  of  modern  methods  of  investigation,  the  constitution 
of  all  the  silicates  may  be  ascertained.  For  instance,  the  results  of 
physical  and  chemical  researches  on  the  silico-molybdates  by 
W.  Asch  are  in  complete  agreement  with  the  H.P.  theory.  This 
agreement  between  the  facts  and  theory  is  very  striking  in  the 
case  of  the  alums  and  chromo-sulphuric  acids  which  have  been 
specially  studied  in  a  chemico-physical  manner  by  Recoura  and 
Whitney. 

There  can  be  no  doubt  that  Nature  has  formed  all  substances 
according  to  monistic  laws.  Hence  the  probability  of  the  H.P.  theory 
being  extended  so  as  to  make  it  applicable  as  a  general  chemical 
theory. 

An  attempt  thus  to  enlarge  the  scope  of  the  H.P.  theory,  though 
made  on  only  a  small  scale,  has  led  to  a  new  theory  of  acids,  new  views 
on  the  constitution  of  solutions  and  new  views  of  the  structure  of 
carbon  compounds. 

The  H.P.  theory  itself  does  not  take  cognisance  of  the  fact  that 
atoms  exist  in  space;  consequently  it  required  extension  and  com- 
bination with  the  modern  theory  of  the  structure  of  crystals  in  order 
to  convert  it  into  a  general  stereo-chemical  theory.  This  has  been  accom- 
plished to  the  extent  that,  by  means  of  the  "  hexite-pentite  law  " 
(p.  289),  the  stereo-hexite-pentite  theory  (abbreviated  to  "  S.H.P." 
theory)  is  capable  of  development  into  a  general  theory  of  chemical 
compounds.  The  S.H.P.  theory  has  proved  to  be  of  great  value  ;  it 
helps  to  explain  many  puzzling  properties  of  crystals,  confirms  Hauy's 
law  of  relationship  between  crystalline  form  and  chemical  composition, 
permits  the  prediction  of  isomers  of  chemically  allied  substances 
(Mitscherlich)  and  solves  the  problem  of  the  structure  of  the  so- 
called  isomorphous  mixtures.  Thus,  the  H.P.  theory  may  be  compared 
to  a  bridge  between  the  realms  of  organic  and  inorganic  chemistry, 
and  the  S.H.P.  theory  to  an  indivisible  bond  between  chemistry  and 
the  allied  sciences  of  physics  and  crystallography. 

The  S.H.P.  theory  appears  to  be  particularly  valuable  when 
it  is  compared  with  existing  theories  of  the  constitution  of 
chemical  compounds.  It  is  then  seen  that  many  modern  theories 
are,  in  a  sense,  only  portions  of  the  new  theory  and  may  be  inferred 
from  it. 

In  a  review  of  the  German  edition  of  the  present  work  by  Stremme767 


324  SUMMARY 

the  following  remark  occurs  :  "In  short,  an  attempt  is  made  to 
develop  a  Chemistry  of  Silicon  corresponding  to  that  of  Carbon  such 
as  has  so  frequently  been  attempted  by  others."  As  a  matter  of  fact, 
the  view  that  Nature  forms  substances  in  accordance  with  monistic 
laws,  permits  many  applications  of  the  results  of  the  study  of  organic 
compounds  (including  their  structural  formulae)  to  inorganic  substances. 
The  critic  must  therefore  ascertain  what  beneficial  results  (if  any)  have 
resulted  from  the  present  investigation  and  whether  previous  investiga- 
tions are  completely  analogous  to  it.  He  is  compelled  to  deny  the 
analogy  if  he  compares  the  results  of  this  investigation  with  previous 
ones.  In  order  to  show  this  more  clearly,  two  investigations  of  the 
relationship  between  the  compounds  of  silicon  and  carbon,  both  of 
great  importance  to  a  study  of  the  structure  of  silicates,  may  here  be 

critically  examined,  viz.  that  of  A.  Safarik768  and  that  of  W.  Ver- 
nadsky769. 

A.  Safarik  has  endeavoured  to  find  a  complete  analogy  between 
silicates  and  organic  compounds  and  has  assumed  that  the  silicates  are 
open  or  closed  ring-compounds  such  as  are  found  in  the  aliphatic  and 
aromatic  compounds  of  carbon.  This  analogy  between  silicon  and 
carbon,  the  former  being  a  constituent  of  the  inorganic  crust  of  the 
earth  and  the  latter  the  foundation  of  all  organic  nature,  "  thus 
assumes  a  new  and  deeper  significance."  In  addition  to  this 

analogy  there  is,  according  to  Safarik,  a  difference  between  the 
compounds  of  silicon  and  carbon  inasmuch  as  in  the  silicates  silicon 
is  bound  to  silicon  through  oxygen  and  the  polyvalent  metals,  whilst 
in  the  organic  compounds  there  is  a  direct  bond  between  carbon  and 
carbon. 

A  glance  at  Safarik's  formula  shows  at  once  that  it  differs  greatly 
from  those  derived  from  the  H.P.  theory.  The  necessary  explanatory 

support  is  lacking  for  Safafik's  theory  of  the  silicates,  and  for  this 
reason  it  cannot  be  applied  to  the  silicates  as  a  whole.  An  important 
disadvantage  of  his  structural  formula  is  due  to  the  fact  that 
it  is  not  based  on  any  natural  law  and  that  it  contains  a  dualism, 
the  origin  of  which  may  be  found  in  the  present  dualistic  con- 
ception of  organic  chemistry,  viz.  the  division  of  organic  compounds 
into  an  aliphatic  and  an  aromatic  series.  The  result  is  that 
this  theory,  notwithstanding  its  derivation  from  organic  chemistry, 

has  not  led  Safaf* ik  very  far.    The  poor  result  which  he  has  obtained 

in  applying  organic  theories  to  inorganic  compounds  caused  Safaf ik  to 
make  the  following  remarks  :  "  The  most  natural  means  of  bringing 
inorganic  chemistry  into  unison  with  the  fundamental  theories  of  the 
present  time  is  that  which  has  led  to  such  remarkably  successful 
results  in  organic  chemistry  ;  each  single  element  must  be  examined 
in  such  a  manner  as  has  been  the  case  with  carbon  or,  as  Erlenmeyer 
so  pregnantly  observed,  we  must  have  as  many  chemistries  as  there 


SUMMARY  325 

are  elements.    To  attempt  this  work  would  be  to  commence  a  task  of 
incredible  magnitude." 

From  these  words  it  is  clear  how  little  satisfaction  Safarik  obtained 
from  his  researches,  and  the  authors  of  the  present  volume  are  equally 
unable  to  accept  the  view  that  the  problems  of  the  structure  of  chemical 
compounds  can  ever  be  solved  by  simply  studying  the  elements  in  a 
systematic  manner.  They  incline  more  to  the  opinion  that  if  the 
present  conception  of  the  structure  of  organic  compounds  cannot  be 
applied  to  inorganic  substances,  then  this  very  inapplicability  is  the 
best  proof  that  the  generally  accepted  theory  of  organic  structures  is 
not  so  devoid  of  objection  that  it  cannot,  with  advantage,  be  modified. 
The  possibility  or  otherwise  of  applying  a  theory  which  appears  to  be 
satisfactory  for  one  element  to  others  is  one  of  the  best  tests  of  the 
value  of  such  a  theory. 

W.  Vernadsky  has  also  endeavoured  to  devise  structural  formulae 
for  silicates  which  bear  some  resemblance  to  those  of  organic  chemistry. 
He  assumed  the  existence  of  two  radicles  in  aluminosilicates  :  one 
with  an  open  or  chlorite  ring  and  the  other  with  a  closed  or  cyclic 
chain  (mica  ring).  The  constitution  of  these  rings  is  shown  by  the 
following  formulae  : 

OH  OH 


/\  /\ 

0    O  0    O 

Si  0=Si     Si=0 

4  A 

\/  \/ 

Al  Al 


Chlorite  Ring.  Mica  Ring. 

According  to  Vernadsky  these  rings  remain  unaltered  in  most 
chemical  reactions,  this  property  being  highly  characteristic  of  the 
aluminosilicates.  The  compounds  with  a  mica  ring  are,  according 
to  this  investigator,  much  more  strongly  characterised  than  minerals 
with  a  chlorite  ring. 

As  the  durability  of  the  rings  is  characteristic  of  cyclic  chemical 
compounds,  and  experience  in  organic  chemistry  shows  that  this 
durability  is  exceptionally  high  in  heterocyclic  compounds,  Vernadsky 
considered  that  it  might  be  assumed  that  minerals  containing 
mica  contain  heterocyclic  rings,  i.e.  rings  composed  of  several 
elements. 

Vernadsky  has  had  no  specially  satisfactory  results  from  this 


326  SUMMARY 

theory  because,  as  he  himself  admits,  it  is  necessary  to  limit  the  applica- 
tion of  the  theory  to  the  simplest  and  best  known  compounds,  and 
because  he  persistently  adheres  to  an  entirely  unnecessary  dualism, 
inasmuch  as  he  divides  silicates  into  two  groups :  one  containing  those 
which  are  undoubtedly  chemical  compounds  and  the  other  comprising 
the  so-called  physical  combinations.  Vernadsky's  theory  is  thus 
inapplicable  as  a  general  theory  of  silicates  and  also  as  a  monistic 
chemical  theory  of  general  application. 

This  short  statement  with  regard  to  important  attempts  to  apply 
the  theories  current  in  organic  chemistry  to  the  elucidation  of  in- 
organic structures  must  suffice  to  show  that  there  is  no  parallel 
between  such  an  application  of  existing  theories  and  the  H.P.  theory 
developed  in  the  present  volume.  Hence,  before  the  H.P.  theory  can  be 
discarded  or  regarded  as  of  no  importance,  those  who  criticise  it  must 
disprove  the  statements  made  and  must  show  that  a  still  larger  number 
of  facts  can  be  fairly  used  in  support  of  a  new  theory  which,  so  far  as 
those  concerned  with  the  writing  and  translation  of  the  present  volume 
are  aware,  has  not  yet  been  published.  The  ineffectiveness  of  all  the 
noteworthy  existing  theories  has,  it  is  believed,  been  conclusively 
shown  in  the  foregoing  pages. 

The  H.P. theory  leads — by  quite  different  means  from  those  hitherto 
used — to  the  "  benzene-ring  theory  "  which  has  proved  so  advantage- 
ous in  studying  the  constitution  and  properties  of  carbon  compounds. 
It  is  scarcely  necessary  to  state  that  Werner's  co-ordination  law  is,  in 
some  respects,  a  part  of  the  S.H.P.  theory.  If  a=6=c=l  and 
a=|8=y=900,  this  produces  Werner's  octohedron,  to  the  corners  of 
which  are  attached  the  molecules  of  various  metal  ammonias  and 
allied  substances.  It  is  a  strong  confirmation  of  the  S.H.P.  theory 
that  Werner's  co-ordination  law  has  solved  a  number  of  puzzling 
problems  in  connection  with  the  metal  ammonias  and  allied  substances, 
that  its  inferences  have  been  fully  confirmed  by  experiment,  and  that 
Werner's  theory  has  proved  of  value  in  the  development  of  a  system- 
atic arrangement  of  the  compounds  concerned. 

Arrhenius'  "Dissociation  Hypothesis."  van't  Hoff's  "Theory  of 
Solutions,"  and  the  Kinetic  Theory  of  Gases  are  all,  in  a  certain 
sense,  capable  of  being  regarded  as  consequences  of  the  S.H.P. 
theory. 

It  is  particularly  important  to  note  that,  by  the  combination  of  the 
S.H.P.  theory  with  the  modern  theory  of  the  structure  of  crystals,  a 
great  step  towards  the  object  of  all  investigation  has  been  made,  and 
some  approach  has  been  effected  to  the  time  when  it  will  be  possible 
to  show  the  true  relationship  between  crystalline  form  and  chemical 
composition.  This  object  will,  clearly,  be  attained  as  soon  as  it  is 
possible  to  ascertain  the  exact  relationship  between  the  geometrical 
constants  (a  :  b  :  c  and  a,  /3  and  y)  and  the  chemical  constants,  and  to 
predict  both  from  the  structural  formula. 

De  Bois-Reymond705  has  no  doubt  that  these  problems  will  be 


SUMMARY  327 

solved  as  soon  as  structural  chemistry  and  crystallography  unite,  and 
he  has  written  the  following  :  "  We  see,  in  imagination,  Structural 
Chemistry  reaching  out  her  hand  to  Crystallography  ;  we  see  the 
atoms  with  their  measured  valencies  filling  spaces  of  definite 
shapes,  and  forming  the  tools  employed  in  building  crystals." 


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Ingenieurvereins   1863  ;    21.  AIC15  in  Alkalies  :    Wormser  u.   Spanjer,  Tonind.-Ztg. 
1899,  1785  ;    22.  Water-glass  :   Heldt,  Journ.  f.  prakt.  Chem.  94,  129  ;    23.  Glycerin  : 
Hardt,  Tonind.-Ztg.  1900,  1674  ;    24.  Sugar  solution  :   Heldt,  Journ.  f.  prakt.  Chem. 
94,  129  ;    Levoir,  Rec.  des  trav.  chim.  des  Pays-Bas  1886,  59  ;    Parsons,  Deutsche 
Topfer-  u.  Ziegler-Ztg.  1888,  585  ;  Masson,  Journ.  Amer.  Chem.  Soc.  16,  733  ;  Rebbufat, 
Tonind.-Ztg.   1899,  782,  823,  883,  900  ;    25.  Ox-blood  :   Mason,  Journ.  Amer.  Chem. 
Soc.  16,  733.     279,  Sehuliatschenko,  Dingl.  Polyt.  Journ.  194,  355.     280,  Michaelis, 
Tonind.-Ztg.  1900,  860.     281,  Jordis  u.  Kanter,  Zeitschr.  f.  angew.  Chem.  1903,  462-8, 
485-92  ;    Hardt,  Tonind.-Ztg.  1900,  1674.     282,  Jordis  u.  Kanter,  I.  c.     283,  Heldt, 
Studien  iiber  die  Zemente,  Journ.  f.  prakt.  Chem.  1865,  207.     284,  Sehuliatschenko, 
Tonind.-Ztg.  1901,  25,  1050,  1053.    284a,  The  cause  of  setting  is  said  to  be  the  formation 
of  aluminates,  and  that  of  hardening  to  be  the  production  of  certain  silicates,  by  Michel, 
Journ.  f.  prakt.  Chem.  1886,  33,  548  ;  A.  Meyer,  Bull.  Boucarest  1901,  Nr.  6.  On  harden- 
ing, the  following  silicates  are  formed  :   1.  CaO  •  SiO2  •  H2O  according  to  Le  Chatelier, 
Bull,  de  la  soc.  chim.  1885,  42,  82  ;    Jex,  Tonind.-Ztg.  1900,  1856-1919  ;    A.  Meyer, 
Bull.  Boucarest  1901,  Nr.  6  ;    Zulkowski,  Broschiire  1901  ;    2.  4  CaO  •  3  SiO2  •  H2O 
according  to  Laudrin,  Compt.  rend.   1883,  96,  156,  379,  841,   1229  ;    3.  5  CaO  •  3  SiO2 

•  H2O  according  to  Michaelis,  Journ.  f.  prakt.  Chem.  100,  257,-303  ;    4.  3  CaO  •  2  SiOa 

•  H2O  according  to  Michaelis,  Verhandl.  d.  Vereins  zur  Bef order,  d.  Gewerbefl.   1896, 
317 ;     5.    2  CaO  •  SiO2  •  H2O    according    to    Rebbufat,    Tonind.-Ztg.    1899,   782,   823, 
853,   1900  ;    A.  Meyer,  Bull.  Boucarest  1901,  Nr.  6  ;    Erdmenger,  Chem.-Ztg.   1893, 
982 ;     6.   3  CaO  •  SiO2  •  H2O    according   to   Rivot  &    Chatoney,    Compt.    rend.    1856, 
153,  302,  785  ;     7.  SiO2  •  H2O  according  to  Kuhlmann,  Compt.  rend.,  Mai  1841  ;    8. 
The  formation  of  calcium  hydrosilicates  was  assumed  by  Berthier,  Ann.  chim.  et  phys. 
22,  62  ;  Fremy,  Compt.  rend.  60,  993  ;  Lieven,  Archiv.  f .  d.  Naturk.  v.  Livland,  Estland, 
u.  Kurland  1864,  4,  45  ;   Michaelis,  Topfer-  u.  Ziegler-Zgt.  1880,  194  ;    9.  A  mixture  of 
basic,  neutral  and  acid  silicates  was  assumed  by  Heldt,  Journ.  f.  prakt.  Chem.  1865, 
94,  124-61  ;    10.  The  formation  of  silicates  without  any  statement  as  to  their  formulae  was 
assumed  by  Vicat  &  John,  Ann.  chim.  et  phys.  5,  387  ;   Feichtinger,  Bayer.  Kunst- 
u.  Gewerbebl.  1858,  69  ;   Winkler,  Chem.  Centralbl.  1858,  482  et  seq.     284b,  Jordis.  u. 
Kanter,  Zeitschr.  f.  angew.  Chem.  1903,  462-8,  485-92.     285,  Le  Chatelier,  Compt. 
rend.  94,  867  ;    Bull,  de  la  soc.  chim.  41,  377  ;    42,  82.     286,  Newberry,  Tonind.-Ztg. 
1898,  879.     287,  Kosmann.  Tonind.-Ztg.  1902,  1895  ;    1895,  237.     288,  Jex,  Tonind.- 
Ztg.  1886,  1919  ;    1900,  1856.     289,  Erdmenger,  Tonind.-Ztg.  1879,  Nr.  1,  19,  20,  49  ; 
Chem.-Ztg.  1893,  982  ;   Dingl.  Polyt.  Journ.  218,  507.     290,  Hardt,  Tonind.-Ztg.  1900, 
1674.     291,  Schonaich-Carolath,   Chem.   Centralbl.    1866,   1062.     292,  Schott,  Dingl. 
Polyt.  Journ.  202,  434.     293,  Zsigmondy,  Chem.   Centralbl.  94,   1064.     294,  Meyer- 
Mahlstatt,  Protok.  d.  Vereins  d.  Portlandzem.-Fabr.  1901.     295,  Rohland,  Zur  Frage 
iiber  die  Konstitut.  d.  Portlandzem.,  Zeitschr.  f.  Baumaterialienkunde,  Nr.  6,  1901, 
20.      For  further   information   on   Constitution   of  Clinkers  see  Fremy,  Compt.  rend. 
60,  993  ;    Sehuliatschenko,  Dingl.  Polyt.  Journ.  194,  355  ;    Michel,  Journ.  f.  prakt. 
Chem.  93,  548  ;    TSrnebohm,  Kongr.  d.  internation.  Verb.  f.  Materialpr.,  Stockholm 
1897  ;  Rebbufat,  Gaz.  chim.  ital.  28,  Teil  II ;  Zulkowski,  Chem.  Ind.  1901,  290  ;  Leduc, 
Sur  la  Dissociation  des  produits  hydraul.,  Sept.   1901  ;    Rivot  u.  Chatoney,  Compt. 
rend.  153,  302,  785;    A.  Meyer,  Bull.  Boucar.  1901,  Nr.  6;  Tonind.-Ztg.  1902,  1895; 
Ludwig,   Tonind.-Ztg.    1901,   2084;   Richardson,  Tonind.-Ztg.   1902,.  1928;   Michaelia, 
Versamml.  d.  Vereins  d.  Portlandzem.-Fabr.  1903  ;    Winkler,  Journ.  f.  prakt.  Chem. 
67,  444  ;  Dingl.  Polyt.  Journ.  775,  208  ;  Heldt,  Journ.  f.  prakt.  Chem.  94,  129,  202-37  ; 


BIBLIOGRAPHY  333 

Laudrin,  Compt.  rend.  96,  156,  379,  841,  1229  ;  Foy,  Ann.  ind.  1887,  90.  296,  Le 
Chatelier,  Compt.  rend.  94,  867.  297,  Tornebohm,  Kongr.  des  internation.  Verb.  f. 
Materialienpr.,  Stockholm  1897.  298,  Richardson,  Baumaterialienk,  1903,  Heft  11, 
150  ;  Tonind.-Ztg.  1903,  Nr.  58.  For  further  information  on  the  use  of  the  microscope  in 
the  study  of  the  constitution  of  Portland  cement  see  W.  Michaelis,  Der  ErhartungsprozeB 
der  kalkhaltigen  hydraul.  Bindemittel,  Dresden  1909,  also  Keisermann,  Der  Port- 
landzement,  seine  Hydratbildung  und  Konstitution,  Kolloidchemische  Beihefte.  Bd. 
I,  1910,  Keisermann  endeavoured  to  ascertain  the  constitution  of  Portland  cement  by 
microscopical  crystallographic  methods  with  the  aid  of  aniline  dyes  as  selective  staining 
agents.  He  concluded  that  clinker  is  probably  a  conglomerate  of  dicalcium  silicate  and 
tricalcuim  aluminate  in  the  proportion  of  4  (2  CaO  •  SiO2)  +  3  CaO  •  A12O3.  Keisermann 
(1.  c.)  and  O.  Schmidt  (Der  Portlandzement,  Stuttgart  1906,  29)  state  that  there  are  now 
in  existence  about  28  theories  of  the  constitution  and  hydratisation  of  cements.  299,  Schott, 
1.  c.  300,  Zulkowski,  Zur  Erhartungstheorie  d.  natiirl.  u.  kunstl.  hydraul.  Kalkes, 
Berlin  1898,  45  ;  Sonderabdr.  a.  d.  Zeitschr.  Chem.  Ind.  1898.  301,  Lunge,  Tonind.- 
Ztg.  1900,  763-5  ;  Zeitschr.  f.  angew.  Chem.  1900,  409.  302,  Schott,  I.  c.  303,  Michaelis, 
Die  hydraulischen  Mfirtel  1869,  193.  303a,  Theories  of  the  process  of  burning  have  been 
published  by  Knipp  (On  burning  the  cohesion  of  the  silica  is  reduced),  Osterr.  Zeitschr. 
f.  Berg-  u.  Hiittenwesen  1865,  Nr.  40  u.  41  ;  Mann  (Burning  draws  the  smallest  particles 
close  together),  Tonind.-Ztg.  1877,  Nr.  26  u.  30;  Michaelis  (Burning  produces  a  state  of 
physical  tension  in  the  molecule),  Journal  f.  prakt.  Chem.  100,  257-303  ;  Erdmenger 
(E.  considered  this  state  of  tension  to  be  partly  chemical),  Tonind.-Ztg.  1878,  232,  250, 
259,  378.  Theories  respecting  the  cause  of  "  dead-burned  "  cement  have  been  published 
by  :  Fremy,  Pettenkofer,  Schonaich-Carolath  who  attributed  it  to  the  formation  of  a 
silicate,  Chem.  Centralbl.  1866,  1062  ;  Vicat  and  many  others  attribute  it  to  the  production 
of  a  fluid  (molten)  material,  Ann.  chim.  et  phys.  1820  ;  Michaelis  has  shown  by  experi- 
ments, that  Vicat's  view  is  erroneous,  Tonind.-Ztg.  1892,  124,  403  ;  Schuliatschenko 
attributed  this  phenomenon  to  physical  causes,  Chem.  News  1869,  190  ;  Hewett  to  an 
allotropic  modification  of  normal  cement,  Tonid.-Ztg.  1899,  211  et  seq.  303b,  The  follow- 
ing papers  have  been  published  on  slag  cements  :  Eisner,  Dingl.  Polyt.  Journ.  106,  32  ; 
Ott,  ibid.  208,  57  ;  Huck,  Polyt.  Centralbl.  1870,  778  ;  Pelouze  and  Fremy,  Berg- 
u.  Hiittenm.  Ztg.  1872,  335  ;  Bodner,  ibid.  1874,  262  ;  Wood,  ibid.  1878,  432  ;  Bosse, 
Tonind.-Ztg.  1885,  Nr.  41  ;  1886,  Nr.  9  ;  Manske,  Zeitschr.  d.  Vereins  d.  Ing.  1885, 
921  ;  Herrmann,  Deutsche  Topfer-  u.  Zeigler-Ztg.  1886,  Nr.  5  ;  Schumann,  Deutsche 
Bauztg.  1886,  4  ;  Tonind.-Ztg.  1886,  Nr.  5  ;  Farinaux,  Tonind.-Ztg.  1886,  Nr.  18-20  ; 
Stahl  u.  Eisen  1886,  Nr.  1  ;  Ausfiihrl.  iiber  Schlackenz.  nach  Tetmajer  in  Tonind.-Ztg. 
1885,  Nr.  36  ;  1886,  Nr.  22  and  Deutsche  Topfer-  u.  Ziegler-Ztg.  1887,  Nr.  26  ;  Knapp, 
Dingl.  Polyt.  Journ.  265,  184  et  seq.  304,  Jantzen,  Tonind.-Ztg.  1903,  Nr.  32.  305, 
Lunge,  I.  c. 

305a,  Theories  of  hardening  :  i.  Physical  reactions  (crystallisations)  the  cause  of 
setting,  according  to  Wolters,  Dingl.  Polyt.  Journ.  1874,  214,  392  ;  Le  Chatelier,  Bull, 
de  la  soc.  chim.  1885,  42,  82  ;  Tonind.-Ztg.  1892,  1032  ;  Levoir,  Rec.  des  trav.  chim. 
des  Pays-Bas  1886,  59  ;  Erdmenger,  Chem.-Ztg.  1893,  982  ;  Rebbufat,  Tonind.-Ztg. 
1899,  782,  823,  853,  900.  2.  The  solidification  or  coagulation  of  the  colloids  produced  on 
mixing  the  cement  with  water  is  the  cause  of  setting  according  to  Hauerschild,  Wochenschr. 
d.  niederosterr.  Gew. -Vereins  1881,  271.  3.  Erdmenger  has  suggested  that  the  dis- 
integrated lime  forces  the  gelatinous  material,  produced  by  the  action  of  water,  into  the 
pores  or  voids  and  so  causes  the  hardening  of  the  mass,  Tonind.-Ztg.  1881,  782,  823,  883, 
900.  4.  Hardening  is  attributed  to  drying  by  Heldt,  Journ.  f.  prakt.  Chem.  1865,  94, 
124-61  ;  Erdmenger,  Tonind.-Ztg.  1880,  Nr.  1,  42.  305b,  A  hydration  of  the  com- 
pounds occurring  in  clinker  is  said  to  occur,  by  Fuchs,  Gesammelte  Schriften,  Miinchen 
1829,  113  ;  Knau6,  Wiirttemb.  Gewerbeblatt  1855,  Nr.  4  ;  Rivot  u.  Chatoney,  Compt. 
rend.  153,  302,  785  ;  Schuliatschenko,  Chem.  News  1869,  190  ;  Knapp.  Dingl.  Polyt. 
Journ.  1887,  265,  184  ;  Perrodil,  Dingl.  Polyt.  Journ.  1885,  255,  76  ;  Le  Chatelier, 
Bull,  de  la  soc.  chim.  1885,  42,  82  ;  Zulkowsky,  I.  c.  300,  Knapp,  Dingl.  Polyt.  Journ. 
1871,  202,  524.  307,  cf.  Knapp,  ibid.  p.  573.  308,  ibid.  p.  518.  309,  Richter,  Zur  Konstit. 
der  Portlandz.  Tonind.-Ztg.  1903,  Nr.  120.  310,  Michaelis,  Die  hydraul.  M6rtel,  p.  577. 
311,  Winkler,  Journ.  f.  prakt.  Chem.  1856,  67,  444.  312,  Winkler,  I.e.  313,  Heldt, 
Journ.  f.  prakt.  Chem.  1865,  94,  129.  314,  Fuchs,  I.  c.  277.  315,  Zulkowski,  tfber  den 
Wahren  Grund  der  Erhartung  der  hydraulischen  Bindemittel,  Chem.  Ind.  1898,  99  ; 
(see  also  31  la).  316,  Von  Teicheck,  Chem.  Ind.  1901,  445.  317,  Zulkowsky,  Chem. 
Ind.  1901,  372.  318,  Zulkowsky,  Chem.  Ind.  1898,  101.  319,  Feichtinger,  Dingl. 
Polyt.  Journ.  1859,  40-61,  108-18.  319a,  "Dber  die  quantitative  Bestimmung  des 
freien  Kalkhydrats  im  erharteten  Zement  N.  Ljamin,  Tonind.-Ztg.  1899,  230  ;  Schuliats- 
chenko, Uber  das  Calciumhydrat  in  dem  erharteten  Portlandzement,  Verhandl. 


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Chem.  1910,  72,  609.  775,  Bose,  Zeit.  fur  Elektrochem.  14,  270.  776,  W.  Asch,  I.  c. 
777,  D.  Asch,  Dissert.  Berlin,  1903.  778,  Fr emery,  Dissert.  Freiberg,  1884.  779,  W. 
J.  Miiller  and  J.  Konigsberger,  Zeits.  fur  angew.  Chemie,  1912,  1273.  780,  W.  Ostwald, 
Zeits.  f.  hys.  Chemie,  81,  Heft  4. 


APPENDIX 

CALCULATION  OF  FORMULAE  FROM   THE   RESULTS 
OF  LEMBERG'S  EXPERIMENTS  * 

A.  Production  of  a  series  of  Sodalites  with  the  general  formula 

m  Na20  •  (6  A1203  •  12  Si02)  •  m'  Salt  •  n  H20 
or  the  formula 

Na12(Si  •  Al  •  Al  •  Si)  •  m'2  •  n  H20 

(a)  The  following  compound 

(6  Na20  •  6  A1203  •  12  Si02)  •  4  NaCl  •  4  H20 
=Na12(Si  •  Al  •  Al  •  SAi)  •  4  NaCl  •  4  H2O 

is  the  final  product  of  the  action  of  a  20  per  cent,  solution  of  caustic  soda 
saturated  with  sodium  chloride  on  the  following  silicates  : 

6  H20  •  6  A1203  •  12  Si02  •    6  H20  (Kaolin  from  Karlsbad) 

=  H12(Si  •  Al  •  A  •  Si)  •  6  H20 
6  Na20  •  6  A1203  •  12  Si02  (Elaolite  from  Brevig) 

=  Na12(Si  •  Al  •  Al  •  Si) 
6  Na20  •  6  A1203  •  18  Si02  •  12  H20  (Brevicite  from  Brevig) 

=  Na12(Si  •  Al  •  Si  •  Al  •  SAi)  •  12  H20 
3  Na20  •  3  A1203  •  12  Si02  •  6  H20  (Analcime  from  Fassthal) 

=  Na6(Si  •  Al  •  Si)  •  6  H20 
3  K20  •  3  A1203  •  12  Si02  (Leucitefrom  Vesuvius) 

=  K6(SAi  •  Al  •  Si) 
3  K20  •  3  A1203  •  18  Si02  (Orthoclase  from  Striegau) 


the  reagent  and  silicate  being  treated  at  various  temperatures  (100°,  180  to 
190°  C.)  for  various  periods  ranging  from  74  hours  to  six  months. 


Theory. 

4 

4f 

4g 

4c 

4d 

4a 

3Na20 

18.51 

19.02 

18.65 

19.35 

19.04 

18.53 

18.57 

3A1203 

30.45 

31.63 

31.81 

31.61 

30.70 

30.84 

30.73 

6SiO2 

35.82 

35.14 

36.32 

36.66 

36.02 

36.42 

36.78 

2  NaCl 

11.64 

10.71 

11.22 

11.32 

10.22 

10.22 

10.23 

2H20 

3.58 

2.61 

0.94 

1.14 

3.60 

3.13 

3.25 

CaO 

— 

0.30 

0.63 

— 

0.14 

0.49 

0.25 

100.00     99.41     99.57     100.08    99.72    99.63     99.81 

*  *  Zeitschr.  d.  Deutsch.  geol.  Gesellsch.  1876-85. 
2  Cf.  pages  60,  61  and  140  of  this  volume. 
»  Cf.  Lemberg,  1.  c.  1883,  p.  582. 

340 


LEMBERG'S   EXPERIMENTS  341 

(b)  After  two  months'  action,  at  100°,  of  15  and  12  per  cent,  solutions  of 
caustic  potash  saturated  with  potassium  chloride  on  the  silicates  * 

3  K20  -  3  A1203  •  12  Si02  (Leucite  from  Vesuvius)      =  K6(SAi  •  Al  •  Si) 

•   /      >A 
3  K2O  •  3  A12O3  •  18  Si02  (Orthoclase  from  Striegau)  =  K6I  Al— Si  I 

V      W 
LEMBERG  obtained  the  sodalite 

(6  K20  •  6  A1203  •  12  Si02)  •  2  KC1  •  8  H20 
=  K12(Si  •  Al  •  Al  •  Si)  •  2  KC1  •  8  H20. 


Theory. 

6c 

6a 

3K2O 

25.77 

24.72 

23.84 

3A1203 

27.96 

27.47 

27.10 

6Si02 

32.89 

32.31 

32.26 

KC1 

6.80 

7.34 

7.00 

4H20 

6.58 

7.80 

8.22 

CaO 

— 

0.30 

— 

100.00        99.94        99.42 
(c)  The  silicates  f 

6  H20  •  6  A1203  •  12  Si02  •    6  H2O  (Kaolin  from  Karlsbad) 

=  H]2(Si  -  Al  •  Al  •  Si)  6  H20 
6  Na20  •  6  A1203  •  18  Si02  •  12  H20  (Brevicite  from  Brevig) 

=  Na12(SAi  -  Al  •  Si  -  Al  •  Si)  12  H2  O 
3  Na20  •  3  A1203  •  12  Si02  •  6  H20  (Analcime  from  Fassthal) 

=  Na6(Si  •  Al  •  Si)  6  H20 
3  K20  •  3  A1203  •  12  Si02  (Leucite  from  Vesuvius) 

=  K6(Sl  •  Al  •  SAi) 
3  Na20  •  3  A1203  •  18  Si02  (Albite  from  Viesch) 


=  Nae 
3  K20  •  3  A1203  •  18  Si02  (Orthoclase  from  Striegau) 


*  Lemberg,  1.  c.  1883,  p.  587. 

t  Lemberg,  I.  c.  1883,  pp.  579,  580. 


342  LEMBERG'S  EXPERIMENTS 

If  a  20  per  cent,  solution  of  caustic  soda,  saturated  with  sodium  sulphate, 
is  used  at  various  temperatures  (100°,  180-190°)  for  different  periods  (74 
hours  to  six  months)  only  the  following  sodalite  is  formed  : 

(6  Na20  •  6  A1203  •  12  Si02)  •  2  Na2S04  •  6  H20 
=  Na12(Si  -  Al  •  Al  •  Si)  •  2  Na2S04  •  6  H20. 


Theory. 

3 

3f 

3a 

3b 

38 

3c 

3d 

3Na20 

17.75 

17.96 

17.75 

17.72 

17.77 

17.39 

17.11 

18.53 

3A1203 

29.20 

30.00 

30.24 

29.44 

29.55 

29.66 

29.01 

30.04 

6Si02 

34.35 

34.31 

34.03 

14.78 

34.29 

35.14 

35.27 

34.74 

Na2S04 

13.55 

11.82 

13.22 

12.65 

11.80 

12.63 

11.21 

9.33 

3H20 

5.15 

5.70 

5.02 

5.35 

5.89 

4.90 

6.25 

5.88 

CaO 

— 

0.35 

— 

— 

0.40 

— 

0.20 

0.20 

100.00     100.14     100.26     99.94    99.70     99.72    99.05     98.72 

(d)  Three  to  five  grammes  of  the  following  silicates  :  * 

6  H20  •  6  A1203  •  12  Si02  •  6  H20  (Kaolin  from  Karlsbad) 

=  H12(Si  •  Al  •  Al  •  Si)  •  6  H20 
6  Na20  •  6  A1203  •  12  Si02  (Elaolite  from  Brevig) 

=  Na12(Si  •  Al  •  Al  •  Si) 
3  Na20  •  3  A1203  •  12  Si02  •  6  H20  (Analcime  from  Fassthal) 

=  Na6(Si  •  M  -  Si)  •  6  H20 
3  K20  •  3  A1203  •  12  Si02  (Leucite  from  Vesuvius) 

=  K6(Si  -  Al  •  Si) 
3  Na20  •  3  A1203  •  18  Si02  (Albite  from  Viesch) 


=  Na,( Al^Si) 

V  \0i/ 


were  mixed  with  40  g.  of  the  sodium  silicate  Na20  •  Si02  •  8  H20,  which 
had  been  melted  in  its  own  water  of  crystallisation  and  the  mixture  heated 
at  200°  for  100  hours  in  a  digester.  The  excess  of  sodium  silicate  was  then 
washed  out  with  cold  water.  An  analysis  of  the  residue  corresponded  to  the 
compound 

(6  Na20  •  6  A1203  •  12  Si02)  •  2  Na2Si03  •  8  H20 

=  Na12(Si  •  Al  •  Al  -  SAi)  •  2  Na2Si03  •  8  H2O. 


Theory. 

3 

3c 

3e 

3f 

3g 

4 

Na20 

23. 

71 

22. 

61 

23 

.30 

23.34 

21. 

03 

21.70 

3 

A1203 

29. 

27 

29 

,31 

28 

.69 

29.16 

29. 

60 

29.25 

7 

Si02 

40. 

15 

40, 

,30 

39 

.43 

40.15 

40. 

52 

40.84 

4 

H20 

6. 

87 

6 

,68 

6 

.88 

6.38 

7. 

49 

6.94 

CaO 

0 

.90 

— 

— 

100.00     98.90     99.20     99.03     98.64    99.73 
*  Lemberg,  I.  c.  1885,  pp.  961,  962. 


LEMBERG'S   EXPERIMENTS  343 

(e)  The  silicates 
6  H20  •  6  A1203  •  12  Si02  •  6  H2O  (Kaolin  from  Karlsbad) 

=  HM(Si  •  Al  -  Al  •  Si)  •  6  H20 
3  Na20  •  3  A1203  •  12  Si02  •  6  H2O  (Analcime  from  Fassthal) 

=  Nae  -  (Si  -  Al  •  Si)  •  6  H2O 
3  K20  •  3  A1203  •  12  Si02  (Leucite  from  Vesuvius) 

=  K6(SAi  •  Al  •  Si) 

were  treated  with  a  15-20  per  cent,  solution  of  caustic  soda  saturated  with 
sodium  carbonate  at  various  temperatures  (100°,  180-190°)  and  for  different 
periods  ranging  from  74  hours  to  six  months.*  Analyses  of  the  products  gave 
the  following  formula : 

3  (6  Na2O  •  6  A1203  •  12  Si02)  •  4  Na2C03  •  30  H20 
=  {Na12(Si  -  Al  -  AJ  •  Si)} 3  '  4  Na2C03  •  30  H20. 


Theory. 

5 

5b 

5c 

9Na20 

18.38 

18.23 

17.17 

18.13 

9  A1202 

30.22 

30.84 

29.18 

29.47 

18  Si02 

35.55 

34.82 

35.50 

35.27 

2  Na2OC3 

6.96 

7.13 

6.96 

6.58 

15H20 

8.89 

8.68 

9.40 

9.18 

CaO 

— 

0.30 

0.10 

0.40 

100.00     100.00     98.84    99.03 

B.  A  Series  of  Changes  in  Aluminosilicates  based  on  Lemberg's 
Experiments. 

(a)  The  action  of  caustic  soda  solution  of  various  concentrations  (30  per 
cent,  and  56  per  cent.)  at  100°  for  various  periods  ranging  from  72  hours  to 
14  days  on  the  following  silicates  : 

(1)  3  Na20  •  3  A1203  •  12  Si02  •  6  H20  (Analcime  from  Fassthal) 

=  Na6(Si  •  Al  •  SAi)  •  6  H20f 

(2)  6  Na20  •  6  A1203  •  12  Si02  (Elaolite  from  Brevig) 

=  Na12(Si  •  Al  •  Al  •  Si)J 

(3)  6  H20  •  6  A1203  •  12  SiO2  •  6  H20  (Kaolin  from  Karlsbad) 

=  H]2(Si  •  Al  •  Al  -  Si)  -  6  H20§ 
gave  the  following  results  : 

From  Compound  1  was  obtained  the  substance  : 

6  Na20  •  6  A1203  •  12  Si02  •  15  H20  =  Na32(SAi  •  Al  •  A!  •  Si)  •  15  H20 
from  Compound  2  the  substance  : 

8  Na20  •  6  A12O3  •  12  Si02  •  7  H2O    =  Na16(Si  •  Al  •  Al  •  Si)  •  7  H20 

*  Lemberg,  I.  c.  1883,  pp.  583-4. 

t  Lemberg,  1.  c.  1883,  p.  579,  Expt.  2. 

j  Lemberg,  L  c.  1885,  pp.  960-1,  Expts.  2c.  and  2d. 

§  Lemberg,  L  c.  1883,  p.  579,  Expt.  1  ;   I.e.  1885,  p.  960,  Expt.  2b. 


344  LEMBERG'S   EXPERIMENTS 

and  from  Compound  3  the  silicates  : 

6  Na20  •  6  A1203  •  12  Si02  •  15  H20  =  Na12(Si  •  Al  •  Al  •  Si)  •  15  H20 
8  Na20  •  6  A1203  •  12  Si02  •  7  H20    =  Na16(Si  •  Al  •  Al  •  Si)  •  7  H20 


Theory. 

1 

2 

6Na20 
6A1203 

18.84 
31.01 

18.30 
31.13 

18.87 
31.35 

12  Si02 
15H20 

36.47 
13.68 

36.52 
14.59 

36.28 
13.39 

100.00 

100.54 

99.89 

Theory. 

2b 

2c 

2d 

8Na20 

25.38 

26.05 

25.29 

24.99 

6A1203 

31.32 

31.42 

31.05 

31.16 

12  Si02 
7H20 
CaO 

36.85 
6.45 

36.25 

6.87 

36.63 
5.71 

1.08 

36.12 
6.36 
1.02 

100.00       100.59      99.76      99.65 

(b)  On  treating  the  silicates  : 

(1)  6  Na20  •  6  A1203  •  12  Si02  (Elaolite  from  Brevig) 

=  Na12(Si  •  Al  -  M  •  Si)* 

(2)  3  Na20  •  3  A1203  •  12  Si02  •  6  H20  (Analcime  from  Fassthal) 

=  Na6(Sl  •  Al  •  Si)  •  6  H20  f 

(3)  3  K20  •  3  A1203  •  18  Si02  (Orthoclase  from  Striegau) 


in  the  state  of  a  molten  glass  with  aqueous  solutions  of  sodium  silicate, 
Na2O  •  22Si02  aq.  of  suitable  concentration,  at  various  temperatures 
(100°,  200-210°)  for  various  periods  (78  hours  to  five  months)  the  following 
substance 

(3  Na20  -  3  A1203  •  15  Si02  •  7J  H20)2 


\     \Sv 


15H20 


was  produced  from  Compounds  1  and  2,  and  the  compound 

3  Na20  •  3  A1203  •  12  Si02  •  6  H20  =  Na6(SAi  •  Al  •  Si)  •  6  H20 
from  the  silicate  3. 

*  Lemberg,  1.  c.  1883,  p.  608,  Expts.  35  and  36. 
t  Lemberg,  I.  c.  1885,  pp.  992-3,  Expts.  42  and  43. 
J  Lemberg,  I.  c.  1885,  pp.  993-4,  Expt.  47. 


LEMBERG'S   EXPERIMENTS 


345 


Theory. 

35 

36 

42 

43 

3Na2O 

12.18 

12.80 

12.64 

12.90 

12.27 

3  A12O3 

20.04 

20.95 

20.64 

20.54 

19.35 

15  SiO2 

58.94 

57.10 

57.67 

57.78 

59.35 

7JH20 

8.84 

8.68 

8.79 

8.78 

9.03 

— 

0.47 

0.30 

— 

— 

100.00 

100.00 

100.04 

100.00 

100.00 

Theory. 

47 

3Na2O 

14.09 

14.01 

3  A1203 

23.20 

22.80 

12  Si02 

54.54 

54.36 

6H20 

8.17 

8.53 

100.00      99.70 
(c)  The  silicate 

3  Na20  •  3  A1203  •  15  SiO2  •  7J  H20  * 

formed  from  the  analcime  from  Fassthal,  after  a  three  weeks'  treatment  with 
potassium  chloride  solution  at  100°  and  a  further  treatment]  for  100  hours 
at  200°,  gave  the  compound 

(3  K20  •  3  A12O3  •  15  Si02  •  1 J  H20)2 


•3H2Of 


Theory. 

42a 

43a 

3  K20          18.62 

19.05 

18.64 

3A1203       20.19 

20.79 

20.25 

15  Si02         59.40 

58.92 

59.90 

1  J  H20           1.79 

1.24 

1.21 

100.00     100.00     100.00 
(d)  The  behaviours  towards  acids  of  the  following  silicates  : 

(1)  0,5  Na2O  •  2,5  CaO  -  3  A1203  •  18  Si02  •  17  H20  (Stilbite  from 
Berufjord)  * 


NaCa2, 


2'5 


i    -17H2Ot 


Si 


(2)  0,5  Na20  •  2,5  CaO  •  3  A12O3  •  18  Si02  •  H20  (Desmine  from  Farsern) 

Si 
=  NaCa2,5    AlSi  -  20  H20  § 


(3)  0,5  K20  •  2  Na2O  •  2,5  CaO  •  5  A12O3  •  18_Si02  -^8H20    (See- 
bachite  from  Richmond)  =  KNa5Ca2,5(Si-  M  •  Si  •  Al  -  Si)  -28  H20|f 

*  Lemberg,  1.  c.  1885,  p.  992,  Expts.  42  and  43. 

f  Lemberg,  /.  c.  1885,  pp.  992-3,  Expts.  42a  and  43a. 

J  Lemberg,  Z.  c.  1885,  pp.  987-8. 

§  Lemberg,  I.  c.  1885,  pp.  989,  990,  993. 

||  Lemberg,  I.  c.  1885,  pp.  972,  977-8. 


346 


LEMBERG'S   EXPERIMENTS 


(4)  0.5  K20  •  2.5  Na20  •  2  CaO  •  5  A120< 
lite  from  Acireale)=  KNa5Ca2(Si  •  Al  •  Si 


18  SiO2 

Al  •  Si)  28 


28H20 


(Hersche- 
H20,*  and  their 


derivatives  are  shown  in  the  following  Tables  I,  II,  III  and  IV,  in  which 

V  =  Lemberg's  Experiment  Number. 

S  =  The  silicates  used. 

A  =  The  salt  solutions  employed. 

Z  =  The  duration  of  the  experiments. 

T  =  The  Temperature. 

P  =  The  Products  obtained. 


Table  I 


V. 

8. 

A. 

Z. 

T 

P. 

39  a 

0.5  NajO'2.5  CaO'3  A1,O,  ) 
•18  SKV17  H2O         I 

KC1  solution 

1.5  Mths. 

100° 

3  K2O'3  AlsOa'18  Si02'13  H20 

39  b 

3  K2O'3  A12O3'18  SiO2'13  H2O 

Naa 

14  Days 

100* 

3  Na20'3  A12O8-18  SiO2'16  H2O 

39  c 

3  Na2O'3  A12O3'18  SiO2'16  H2O 

Nad       „ 

1355  Hrs. 

210-220° 

3  Na20-3  AljOj'18  Si02'8  H2O 

39  d 

3  Na20'3  AlaO3'18  SiOa'16  H2O 

(Na20-  Si02+NaCl)       ., 

75Hrs. 

195-205° 

3  Na20'3  A1203'18  SiO2'8  H2O 

39  g 

3  Naa0'3  Ala03'18  Si02'16  H2O 

(Borax+NaCl) 

78  Hrs. 

200-210° 

3  Na20'3  A12OS'18  Si02'8  H2O 

39  h 

3  NaaO'3  A12O3-18  SiOa'16  H2O 

(Borax  +NaCl) 

78  Hrs. 

200-210° 

3  Na2O'3  AI203'18  Si02'8  H2O 

39k 

3  NaaO'3  AIaO3'18  SiOa'16  H2O 

(Na2HP04+NaCl)       ,. 

74  Hrs. 

220° 

3  Na2O'3  A12OS'18  Si02'8  H2O 

39  e 

3  Naa0'3  A1203'18  Si02'8  H2O 

Ka     .. 

75  Hrs. 

200° 

3  K2O'3  A1203  18  SiO2'H2O 

391 

3  Na2O'3  AljO8-18  Si02'8  H2O 

KC1 

78  Hrs. 

210-215° 

3  K2O'3  A12O3-18  Si02'H2O 

391 

3  Na2O'3  A12O3'18  SiO2'8  H2O 

KC1       ., 

79  Hrs. 

210° 

3  K2O-3  AI2O,'18  Si02'H2O 

39  f 

3  K20'3  Al2Oa'18  SiO^'HsO 

NaCl       „ 

6  Days 

100° 

3  Na2O'3  A12O,'18  Si02'8  H2O 

Theory. 

39 

0.5  Na20 

1.66 

1.40 

2.5  CaO 

7.53 

7.43 

3     A1203 

16.26 

16.48 

18    SiO2 

58.09 

57.97 

17    H20 

16.46 

16.20 

K20 

— 

0.52 

100.00      100.00 


Analyses 


Theory. 

39a 

3K20 

14.82 

14.30 

3  A1203 
18  SiO2 

16.09 

56.78 

16.34 
57.21 

13H2O 

12.31 

12.85 

Theory. 

39b 

3Na20 

10.00 

8.89 

3  A1203 

16.45 

16.72 

18  Si02 

58.07 

58.14 

16H20 

15.48 

15.47 

CaO 

— 

0.78 

100.00     100.70 


100.00     100.00 


Lemberg,  I.  c.  1885,  pp.  976,  979. 


LEMBERG'S   EXPERIMENTS 


547 


Theory. 

39c 

39d 

39g 

39h 

39k 

39f 

3Na20 

10 

.84 

10 

.61 

10 

.94 

11. 

27 

11.07 

10.74 

10.81 

3A1203 

17 

.84 

17 

.56 

17 

.99 

17. 

74 

17.56 

18.21 

17.71 

18  Si02 

62 

.94 

62 

.56 

62 

.54 

62. 

22 

62.68 

62.32 

62.87 

8H20 

8 

.38 

9 

.27 

8 

.53 

8. 

77 

8.69 

8.73 

8.61 

100.00  100.00  100.00  100.00  100.00  100.00  100.00 


Theory. 

39e 

39i 

391 

3  Na20          16.73 

16.66 

16.87 

16.63 

3  A1203         18.10 

18.15 

18.00 

18.72 

18  SiO2           64.09 

64.27 

63.89 

63.41 

H2O             1.08 

0.92 

1.24 

1.24 

100.00     100.00     100.00     100.00 

The  experiments  shown  in  Table  I  indicate  a  replacement  of  the  mono- 
and  di-valent  elements  and  a  variation  of  the  water  in  compounds  of  the 
type 


Table  II 


V. 

S. 

A. 

z. 

T. 

P. 

40  a 

0.5  Na2O'2.5  CaO'3  A1208'18  Si02'20  H2O 

KC1  sol. 

1  Month 

100° 

3  K,O'3  A120,'18  Si02'13  H20 

40  b 

3  K20'3  A120S'18  SiOj'13  H2O 

NaCl    .. 

14  Days 

100° 

3  Na20'3  A12O,'18  Si02'16  H20 

40  c 

3  Na2O-3  A12O2'18  Si02'16  H20 

NaCl   ,. 

1029  Hrs. 

210-220° 

3  Na2O'3  A12OS'18  Si02'8  H20 

40  d 

3  Na2O'3  A1208'18  Si02'16  H20 

(Na20-2SiO,+NaCl)   .. 

74  Hrs. 

220° 

3  Na20-3  A120S'18  SiO2'8H2O 

40  f 

3  Na2O'3  A1203'18  Si02'16  H2O 

(Borax  +NaCl)   ,. 

186  Hrs. 

210-220° 

3  Na2O'3  A1203'18  Si02'8  H2O 

40  e 

3  Na2O'3  A120S-18  Si02'8  H2O 

KC1    .. 

79  Hrs. 

210" 

3  K2O'3  A12OS'18  SiO2-H2O 

40  g 

3  Na20-3  A1208'18  Si02'8  H2O 

KC1    .. 

79  Hrs. 

210-220° 

3  K2O'3  A12O3'18  Si02'H2O 

44 

0.5  Na20'2.5  CaO'3  A120,'18  Si02'20  H2O 

20%Na2CO,    ,. 

15  Mnths. 

100° 

3  Na20'3  A120S'15  SiO2'7i  H2O 

44  a 

3  Na20'3  A1208'15  Si02'7i  H2O 

Ka  ,. 

100  Hrs. 

200" 

3  K2O'3  A120S'15  SiO2'li  H20 

45 

0.5  Na2O'2.5  CaO'3  AJ20S'18  Si02'20  H2O 

25%Na20'Si02   ,. 

2  Mnths. 

100° 

3  Na20'3  A1208'12  Si02'6  H2O 

45  a 

3  Na2O'3  A1208'12  SiO2'6  H2O 

Ka  .. 

3  Weeks 

100° 

3  K2O'3  AI20,'12  Si02'H2O 

Analyses 

Theory. 

40 

0.5  Na20            1.60 

0.91 

2.5  CaO              7.31 

7.60 

3     A12O3          15.96 

16.18 

18     Si02           56.36 

56.62 

20    H2O           18.77 

18.63 

K20             — 

0.24 

100.00     100.18 


348 


LEMBERG'S  EXPERIMENTS 


Theory.  40a 

3  K20            14.82  14.42 

3  A1203          16.09  15.83 

18  SiO2           56.78  56.81 

13  H2O            12.31  12.94 


Theory.  40b 

3  Na2O          10.00  9.74 

3  A1203          16.45  16.35 

18  SiO2           58.07  57.09 

16  ELO            15.48  16.82 


100.00     100.00 


100.00     100.00 


Theory. 

40c 

40d 

40f 

3  Na20 

10.84 

10.63 

11.12 

11.46 

3A1203 

17.84 

17.62 

17.83 

17.73 

18  Si02 

62.94 

62.48 

62.08 

61.87 

8H20 

8.38 

9.27 

8.97 

8.94 

100.00     100.00     100.00     100.00 


Theory. 

40e 

40g 

3K20 

16.73 

17.18 

17.11 

3A1203 

18.10 

18.51 

18.39 

16  SiO2 

64.09 

62.77 

62.95 

H20 

1.08 

1.54 

1.55 

Theory. 

44 

3Na20 
3  A1203 
15  Si02 

12.18 

20.04 
58.94 

11.84 
19.79 
59.93 

7iH20 

8.84 

8.44 

100.00     100.00     100.00 


100.00     100.00 


Theory. 

44a 

3K20 

18.62 

18.19 

3A1203 

20.19 

20.21 

15  SiO2 

59.40 

60.90 

liH20 

1.79 

0.70 

100.00     100.00 


Theory. 

45 

3Na2O 

14.09 

13.72 

3A1203 

23.20 

22.14 

12  Si02 

54.54 

55.26 

6H20 

8.17 

8.88 

100.00 

100.00 

Theory. 

45a 

3K20 

21.26 

20.78 

3  A1203 
12  Si02 
H20 

23.09 
54.30 
1.35 

22.54 
55.53 
1.15 

100.00     100.00 

From  the  results  shown  in  Table  II  it  will  be  seen  that  there  occur  : 
1.  A  substitution  of  the  mono-  and  di-valent  elements  of  compounds 
of  the  type 


and  a  substitution  of  mono-valent  elements  in  compounds  of  the  types 

•Si) 


(S\ 
Al^-Si  I  and  R6  (Si  •  Al  *  & 
XSi/ 


LEMBERG'S   EXPERIMENTS 

2.  A  conversion  of  the  compounds  of  the  type 


349 


l     Si 


into  those  of  the  types 


R6    AlSi    and  R6(Si  •  Al  •  Si) 


3.  A  change  in  the  water-content  is  observable  in  some  cases. 


Table  III. 


V. 

S. 

A. 

Z. 

T. 

P. 

26  a 

0.5  K20'2  NajO'2.5  CaO'5  A120,  \ 
•18  SiO2'28  H2O              / 

KC1  Solution 

2  Mtbs. 

100° 

5  K2O'5  AlaOj'18  Si02'24  H20 

26  b 

0.5  K20'2  Na2O-2.5  CaO'5  A120,  \ 
•18  SiOj'28  H2O              / 

(8%KaCO«+15%Ka)     .. 

70Hrs. 

200-210° 

5  K2O'5  A12O,'18  SiOj'24  H20 

26  c 

5  K2O'5  A1,OS'18  SiO2'24  H2O 

NaCl      ,. 

20  Days 

100° 

5  Na,0'5  A1203'18  Si02'27  H2O 

26  d 
26  f 
26  e 

5  K2O'5  A12O8'18  SiO2'24  H2O 
5  K2O'5  A12O,'18  SiO2-24  H2O 
5  Na,0'5  A12O,'18  SiOj'10  H2O 

(15%NaCl+5%Na2CO,).. 
(15%  NaQ+5%  Na2CO»)  ,. 
KC1       „ 

150  Hrs. 
150  Hrs. 
100  Hrs. 

200-210° 
200-210° 
200-215° 

5  Na2O'5  A120S'18  Si02'10  H2O 
5  Na2O'5  A12O,'18  SiO2'10  H20 
5  K2O'5  A120,'18  SiO2'H2O 

26  g 

5  Na2O'5  A120,'18  SiOj'10  H2O 

KC1       ,. 

100  Hrs. 

210° 

5K20-5Al20,'18Si02-H20 

Theory. 

26 

0.5  K20 
2Na20 
2.5  CaO 

1.94 
5.09 

5.78 

2.00 
4.92 
5.89 

5  A1203 

18  Si02 

21.04 
44.54 

21.66 
44.30 

28H20 

21.61 

21.23 

Analyses 

Theory. 

26a 

26b 

5K20 

18.87 

18.85 

18.65 

5  A1203 

20.48 

20.43 

20.49 

18Si02 

43.35 

43.75 

44.21 

24H20 

17.30 

16.96 

16.65 

100.00   99.99  100.00 


100.00  100.00 


Theory. 

26c 

5  Na20 
5  A1203 
18  SiO2 
27H20 

12.98 
21.44 
45.23 
20.35 

12.89 
21.27 
45.44 
20.40 

100.00 

100.00 

Theory. 

26d 

26f 

5Na20 

14.91 

14.98 

14.98 

5A1203 

24.52 

24.68 

24.33 

18  Si02 

51.92 

51.59 

52.05 

10H2O 

8.65 

8.75 

8.64 

100.00  100.00  100.00 


Theory. 

26e 

26g 

5  K20           22.62 

21.86 

21.64 

5  A12O3         24.54 

25.87 

25.31 

18  Si02           51.97 

51.70 

52.49 

H20             0.87 

0.57 

0.56 

100.00  100.00  100.00 


350 


LEMBERG'S   EXPERIMENTS 


Table  IV 


V. 

S. 

A. 

Z. 

T. 

P. 

27  a 

0.5  K,O'2.5  Na2O'2  CaO'5  A1»0S  \ 
•18  SiOj'28  HaO               f 

KC1  Solution 

1  Mth. 

100" 

5  K,O'5  Al20a'18  Si02'24  H»0 

27  b 

0.5  KjO'2.5  Na,O'2  CaO'5  A120S  ) 
•18  SiOj'28  H2O               f 

(15%KC1+8%K2C03)      .. 

150  Hrs. 

210-220° 

5  K2O'5  A1202-18  SiOt'16  H2O 

27  c 

5  KjO'o  A1203'18  SKV24  H2O 

NaCl      ., 

18  Days 

100° 

5  Na20-5  A12OS'18  Si02'27  H2O 

27  d 

5  Na2O'5  A12O3'18  SiO2'27  H2O 

(15%NaCl+5%Na2C03)  „ 

170  Hrs. 

210-220° 

5  Na20'5  Al2Os-18Si02'10H2O 

27  e 

5  Na2O'5  A1203'18  SiO2'10  H2O 

KC1      .. 

75  Hrs. 

200-210° 

5  K2O'5  A1203'18  SiO2'H2O 

27  f 

5  K20'5  A1203'18  Si02'H2O 

NaCl      ,. 

10  Days 

100" 

5  Na2O'5  A120S'18  SiO,'10  H20 

Analyses 


Theory. 

27 

0.5  K2O 

1.94 

1.27 

2.5  Na20 
2CaO 

6.40 
4.55 

6.76 
5.05 

5A1203 
18  SiO2 
28H2O 

21.03 
44.49 
21.59 

21.27 
44.12 
21.57 

Theory. 

27a 

5K20 

18.87 

18.67 

5  A1203 

20.48 

20.41 

18  Si02 

43.35 

44.08 

24H20 

17.30 

16.84 

100.00     100.00 


100.00     100.04 


Theory. 

27b 

5K20 

20.02 

19.55 

5A1203 

21.72 

21.96 

18  Si02 

45.99 

46.34 

16H2O 

12.27 

12.15 

100.00 

100.00 

Theory. 

27d 

27f 

5Na20 

14.91 

14.97 

14.86 

5  A1203 

24.52 

24.52 

24.44 

18  SiO2 

51.92 

51.96 

52.16 

10H2O 

8.65 

8.55 

8.54 

Theory. 

27c 

5Na20 

12.88 

12.50 

5  A1203 

21.44 

21.28 

18  Si02 

45.33 

45.68 

27H20 

20.35 

20.54 

100.00 

100.00 

Theory. 

27e 

5K20 

22.62 

21.57 

5  A1203 
18  Si02 

24.54 
51.97 

25.20 
52.74 

H20 

0.87 

0.49 

100.00     100.00     100.00 


100.00     100.00 


From  the  results  given  in  Tables  III  and  IV  there  is  clearly  a  substitution 
of  the  mono-  and  di-valent  elements  in  the  type 

R10  (Si  •  AT  •  Si  •  Al  •  Si) 

and  in  one  case  (Table  IV,  No.  27d)  a  change  in  the  water-content, 
(e)  The  formation  of  compounds  of  the  type  * 

5.5  R20  •  6  A12O3  •  16  Si02  =  Ru(Si  •  Al  •  Si  •  Al  •  Si). 

On  treating  two  molecules  of  K2O  •  Si02  with  one  molecule  of  H20  •  K2O 
•  A1203  LEMBERG  obtained  the  substance 

0.5  Na20  •  5  K20  •  6  A12O3  •  16  Si02  =  NaK10  "(Si  •  Al  •  Si  •  Al  •  Si)  f 


*  Lemberg,  I.  c.  1876,  pp.  574-5. 
t  Expt:  1,  L  c.  p.  574. 


LEMBERG'S  EXPERIMENTS 


351 


On  treating  this  silicate  for  a  further  period  of  7  or  18  days  at  the  ordinary 
temperature  with  variable  quantities  of  solutions  of  sodium  chloride, 
potassium  chloride,  etc.,*  LEMBERG  obtained  compounds  whose  analyses 
corresponded  to  the  general  formula 

5.5  R20  •  6  A1203  •  16  SiO2  =  Ru(Si  •  Al  •  Si  •  Al  •  Si) 

16  Si02  (Expt.  2b) 

16  Si02  (Expts.  la,  Ig,  2a,  2c) 

16Si02(Expts,  lb,  If,  2d) 

16  SiO2  (Expts.  Ic,  le) 

16Si02(Expt.  Id) 

16  Si02  (Expt:  2) 

16  Si02  (Expt.  4b) 

16  Si02  (Expts.  4a,  4c) 

16  Si02  (Expt.  4d) 

16Si02(Expt.  4) 

16  Si02  (Expts.  3a,  3b,  3c) 

16  Si02  (Expt.  3d) 

16  Si02  (Expt.  3). 


Na20 

•   4.5  K20 

•  6  A1203  • 

2Na20 

•    3.5  K20 

•  6  A1203  • 

2.5  Na20 

•      3K20 

•6A1203- 

3Na2O 

•    2.5  K2O 

•  6  A1203  • 

3.5  Na2O 

•       2K20 

•  6  A12O3  • 

5Na2O 

•    0.5  K2O 

•  6  A1203  • 

1.5  K20 

•      4  MgO 

•  6  A1203  - 

2K20 

•    3.5  MgO 

•  6  A1203  • 

2.5  K2O 

•      3  MgO 

•  6  A1203 

3K20 

•    2.5  MgO 

•  6  A1203  • 

1.5  K2O 

•      4  CaO 

•  6  A1203 

2K2O 

•    3.5  CaO 

•  6  A1203  • 

2.25  K20 

•  3.25  CaO 

•  6  A1203  - 

Theory. 

1 

0.5  Na2O 

1.50 

1.83 

5K20 

22.67 

22.75 

6A1203 

29.52 

29.38 

16  Si02 

46.31 

46.04 

100.00     100.00 


Theory. 

2b 

Na20 

3.02 

2.55 

4.5  K2O 

20.56 

21.21 

6A1203 

29.75 

30.60 

16  Si02 

46.67 

45.64 

100.00     100.00 


Theory. 

la 

Ig 

2a 

2c 

2Na20 
3.5  K20 

6.12 
16.25 

6.41 
16.00 

6.67 
15.40 

5.98 
16.37 

5.91 
16.79 

6A1203 
16  Si02 

30.22 
47,41 

29.99 
47.60 

29.88 
48.05 

30.40 
47.25 

30.30 
47.00 

100.00     100.00     100.00     100.00     100.00 


Theory. 

lb 

If 

2d 

2.5  Na20 

7.72 

7.54 

7.52 

7.54 

3K20 

14.04 

14.12 

14.03 

14.71 

6A1203 

30.46 

29.74 

30.00 

30.00 

16  Si02 

47.78 

48.60 

48.45 

47.75 

100.00     100.00     100.00     100.00 


*  In  the  cases  mentioned  the  salt  solutions  were  of  a  definite  concentration.     The 
salts  were:    NaCl-,  KC1-,  MgCla-,  CaCla-,  (NaCl+KCl)-,  (MgCl2-f-KCl)-,  (CaCla+KCl). 


352 


LEMBERG'S   EXPERIMENTS 


Theory. 

Ic 

le 

Theory. 

Id 

3 

2.5 
6 
16 

Na2O 
K20 
A1203 
Si02 

9.33 
11.79 
30.71 

48.17 

8.97 
11.89 
30.12 
49.02 

8.78 
12.10 
30.13 

48.99 

3.5  Na20         10 
2     K20            9 
6     A1203        30. 
16  Si02          48. 

.97 

.57 
96 
50 

11.19 
8.95 
30.29 
49.57 

100.00 

100.00 

100.00 

100.00 

100.00 

Theory. 

2 

Theory. 

4b 

5 
0.5 
6 
16 

Na20 
K2O 
A1203 
Si02 

16.07 
2.43 
31.73 
49.77 

15.60 
3.21 
31.20 
49.99 

1.5  K20            7. 
4    MgO            8. 
6     A1203        32, 
16  Si02          51, 

52 
54 

68 
26 

7.94 
8.33 
32.29 
51.44 

100.00 

100.00 

100 

.00 

100.00 

Theory. 

4a 

4c 

Theory. 

4d 

2 
3.5 
6 
16 

K2O 
MgO 
A1203 
Si02 

9.89 
7.36 
32.22 
50.53 

10.03 
6.97 
31.72 
51.28 

10.01 
7.03 
31.60 
51.36 

2.5  K20           12. 
3    MgO            6. 
6     A1203        31, 
16  Si02          49. 

19 
23 
76 

82 

11.59 
6.37 
31.69 
50.35 

100.00 

100.00 

100.00 

100. 

00 

100.00 

Theory. 

4 

3     K20 
2.5  MgO 
6    A1203 

14.43 
5.12 
31.32 

13.72 
4.94 
31.80 

16  Si02 

49.13 

49.19 

100.00 

99.65 

Theory. 

3a 

3b          3o 

1.5 

K2O 

7.28 

7.75 

6.42        7.32 

4 

CaO 

11.57 

11.07 

12.14       10.99 

6 
16 

A1203 
Si02 

31.60 
49.55 

30.91 
50.27 

31.20      31.00 
50.24      50.79 

100.00 

100.00 

100.00     100.10 

Theory. 

3d 

Theory. 

3 

2 
3.5 

K20 
CaO 

9.61 
10.02 

8.81 
10.10 

2.25  K20         10. 
3.25  CaO           9. 

76 
26 

10.87 
9.22 

6 
16 

A1203 
Si02 

31.29 

49.08 

31.03 
50.06 

6  A1203       31. 
16  SiO2        48. 

13 

85 

30.64 
49.23 

100.00  100.00 


100.00   99.96 


THE   TOPAZ   GROUP 


353 


The  Topaz  Group 

The  following  analyses  of  the  Topazes  conform  to  compounds  of  the  type 

Al  -  Si  •  Al  =  6  A1203  •  6  SiO2 
and  to  the  following  formulae  : 


(a)  SieAluO*  F18, 

(b)  Si6Al12025.5Fl9, 

(c)  Si6Al12025  F110, 

(d)  SieAl^O^gFl^, 

(e)  Si6Al12024  F112. 


SiOj 

A1203 

Fl 

Total 

Source 

Analyst 

(a)  Si6Al12026Fl8. 

Theory 

33.97 

57.74 

14.34 

106.05 





I 

34.24 

57.45 

14.99 

107.37 

Schneckenstein 

Berzelius1  * 

XII 

34.36 

57.74 

15.02 

107.12 

Finbo 

Berzelius2 

XXII 

34.01 

58.38 

15.06 

107.45 

Brazil 

Berzelius3 

(b)  Si6Al12025.5Fl9. 

Theory 

33.62 

57.14 

15.97 

106.73 

— 



XXIV 

33.73 

57.39 

16.12 

107.24 

Brazil 

Rammelsberg4 

XXV 

33.15 

57.01 

16.04 

106.20 

Pikes  Peak 

Hillebrand6 

(c)  Si6Al12025Fl10. 

Theory 

33.25 

56.55 

17.56 

107.36 

— 



IV 

33.35 

56.53 

17.69 

107.57 

Altenberg 

Klemm8 

V 

33.23 

56.20 

17.37 

106.80 

Altenberg 

Klemm7 

VI 

33.38 

56.32 

17.26 

106.96 

Altenberg 

Klemm8 

XIV 

33.72 

56.10 

17.20 

107.02 

Finbo 

Klemm9 

XV 

33.57 

56.30 

17.00 

106.87 

Finbo 

Klemm10 

XVI 

33.64 

56.24 

17.12 

107.00 

Finbo 

Klemm11 

XVIII 

33.68 

56.36 

17.11 

107.15 

Miask 

Klemm18 

XIX 

33.19 

56.72 

17.09 

107.00 

Miask 

Klemm13 

XXI 

33.24 

57.02 

17.64 

108.73 

Tasmania 

Sommerland1' 

(d)  Si6Al12024.5Fln. 

Theory 

32.93 

55.97 

19.12 

108.02 





III 

33.53 

56.54 

18.62 

108.69 

Schneckenstein 

Rammelsberg15 

X 

32.28 

55.86 

18.28 

106.42 

Zinnwald 

Rammelsberg1' 

XI 
XX 

33.27 
33.56 

56.76 
56.28 

18.54 
18.30 

108.67 
106.14 

Schlaggenwald 
Adun-Tschilon 

Rammelsberg17 
Rammelsberg  x  8 

*  References  to  the  Literature  are  given  on  p.  438  et  eeq. 


2  A 


354 


THE   EPIDOTES 


The  Epidotes 

The  following  analyses  of  the  Epidotes  conform  to  compounds  of  the  type 

Si  •  Al  •  Al  •  Si  =  6  A1203  •  12  Si02 
or  to  the  general  formula  : 


4 

H20- 

(a) 
(b) 
(c) 
(d) 
(e) 
(f) 
(g) 
(h) 
(i) 

16 
4 
4 
4 
4 
4 
4 
4 
4 
4 

CaO 
H20 
H20 
H20 
H2O 
H20 
H20 
H20 
H20 
H20 

•  2  (6  R20 
-  16  CaO  • 
•  16  CaO  • 
•  16  CaO  • 
•  16  CaO  • 
•  16  CaO  • 
•  16  CaO  • 
•  16  CaO  • 
•  16  CaO  • 
•  16  CaO  • 

3  •  12  Si02) 
2  Fe203  • 
2.25  Fe203  • 
2.5  Fe2O3  - 
2.75  Fe2O3  • 
3Fe203- 
3.25  Fe203  • 
3.5  Fe203  • 
3.75  Fe203  • 
4  Fe203  • 

(12  R203  = 
10  A1203  • 
9.75  A1203  • 
9.5  A1203  • 
9.25  A12O3  • 
9A1203- 
8.75  A1203  • 
8.5  A12O3  • 
8.25  A1203  • 
8  A1203  • 

mFe203nAl203). 
24  SiO2. 
24Si02. 
24Si02. 
24  Si02. 
24Si02. 
24  SiO2. 
24Si02. 
24  Si02. 
24Si02. 

Si02 

A120, 

FeaOs 

CaO 

HaO 

FeO 

Total 

Source 

Analyst 

(a)  4  H20  •  16  CaO  •       2  Fe203  •     10  A12O3  •  24  Si02. 

Theory 

38.44 

27.21 

8.54 

23.90 

1.91 

100.00 





III 

39.18 

26.52 

8.21 

23.89 

2.20 

100.00 

Zoptau 

Nanke1  * 

XVI 

38.42 

26.62 

8.72 

23.66 

2.46 

99.88 

Sustenhorn 

Stockar-Escher2 

XVII 

38.43 

26.18 

8.77 

24.13 

2.46 

99.97 

Sustenhorn 

Stockar-Escher3 

XX 

37.66 

27.36 

8.90 

23.90 

2.33 

100.15 

Caverdiras 

Stockar-Escher* 

XXI 

38.08 

27.74 

8.27 

23.53 

2.04 

99.66 

Maggiatal 

Stockar-Escher5 

XXII 

38.28 

27.53 

8.66 

22.87 

2.41 

99.75 

Formarzatal? 

Stockar-Escher6 

XLIV 

37.92 

27.90 

9.10 

22.81 

2.02 

99.75 

Pargas 

Wilk7 

(b)  4  H20  •  16  CaO  •  2.25  Fe2O3  •  9.75  A1203  •  24  Si02. 

Theory 

38.28 

26.43 

9.57 

23.81 

1.91 

100.00 



— 

XIV 

37.96 

26.35 

9.71 

23.77 

2.02 

99.81 

Guttannen 

Stockar-Escher8 

XV 

38.13 

26.42 

9.74 

23.30 

2.02 

99.61 

Guttannen 

Stockar-Escher9 

XXXIV 

37.87 

24.72 

9.96 

23.10 

2.82 

0.36 

100.14a 

Mainland 

Heddle10 

(c)  4  H2O  •  16  CaO  •    2.5  Fe2O3  •    9.5  A12O3  •  24  Si02. 

Theory 

38.13 

25.65 

10.59 

23.72 

1.91 

100.00 

— 

— 

XIII 

38.99 

25.75 

9.99 

23.76 

2.05 

0.61  MgO 

100.16 

Guttannen 

Scheerer11 

XLI 

38.84 

25.45 

10.88 

22.62 

2.41 

100.20 

Arendal 

Richter12 

(d)  4  H2O  •  16  CaO  •  2.75  Fe203  •  9.25  A1203  •  24  Si02. 

Theory 

38.00 

24.90 

11.60 

23.62 

1.88 



100.00 

_            i             _ 

LIII 

37.47 

24.09 

10.60 

22.19 

2.24 

2.81 

99.40 

Achtenskoi       Hermann  1  3 

LIX 

38.20 

24.62 

12.20 

21.59 

2.16 

0.57  MnO 

99.846 

Rowe,  Mass.    JA.  G.  Dana14 

(e)   4  H20  •  16  CaO  •       3  Fe203  •       9  A1203  •  24  Si02. 

Theory 

37.84 

24.12 

12.61 

23.54 

1.89 



100.00 

— 

— 

VIII 

38.60 

23.08 

12.34 

24.17 

1.88 

0.95 

101.02 

Sulzbachtal 

Mauthner15 

IX 

36.90 

24.36 

12.40 

23.54 

2.01 

0.72 

lOO.OOe 

Sulzbachtal 

Laspeyres18 

XXXII 

38.26 

24.75 

11.07 

23.63 

2.26 

0.56 

100.53 

Quenast 

Renard17 

XXXVII 

37.32 

22.85 

11.56 

22.13 

2.93 

1.86 

99.32d 

Arendal 

Hermann18 

a  Inch  0.54  MnO  •  0.77  MgO. 

6  Inol.  0.07  MnO. 

*  For  references  see  p.  438. 


c.  Inch  0.13  MgO  •  0.37  Alkalies. 
d  Incl.  0.77  MgO. 


THE   GRANITES 


355 


SiO, 

A1.0, 

Fe208 

CaO 

H»O 

FeO 

Total 

Source 

Analyst 

(f)    4  H2O  •  16  CaO  •  3.25  Fe2O3  •  8.75  A12O3  •  24  Si02. 

Theory 

37.70 

23.37 

13.601  23.45 

1.881 

100.00 



IV 

38.37 

22.09 

13.77  22.90 

2.11 

99.24 

Sulzbachtal 

v.  Drasche19 

VI 

37.83 

23.43 

13.3l|  23.47 

2.06|      0.48 

100.58 

Sulzbachtal 

Ludwig80 

(g)  4  H20  •  16  CaO  -    3.5  Fe2O3  •    8.5  A12O3  •  24  Si02. 

Theory 

37.55 

22.61 

14.60 

23.36 

1.88 

100.00 



V 
XXX 

LVIII 

37.83 
36.71 
37.04 

22.63 
22.61 
22.99 

14.02 
14.47 
14.19 

23.27 
23.67 
24.09 

2.05 
1.92 
2.16 

0.93 
0.62 

100.73 
100.00 
100.47 

Sulzbachtal 
"Bourg  d'Osians" 
Hereroland 

Ludwig21 
Laspeyres22 
Wulf23 

(h)  4  H20  •  16  CaO  •  3.75  Fe203  •  8.25  A12O3  •  24  Si02. 

Theory 

37.40 

21.861  15,59 

23.28 

1.87 

100.00 



VII 

37.11 

21.90|  16,00 

23.19 

2.03 

100.23 

Sulzbachtal 

Rammelsberg24 

(i)    4  H20  •  16  CaO  •  4  Fe2O3  •  8  A1203  •  24  Si02. 

Theory 

37.27 

21.11  16.56  23.1911.87 

__ 

100.00                  —                             _ 

XXIII 

37.65 

20.64 

16.50 

22.32  2.06 

0.49MnO 

100.12 

Traversella 

Scheerer25 

XXVIII 
XXIX 
XXXVII 
XL 

37.56 
37.35 
38.76 
37.59 

20.78 
22.02 
20.36 
20.73 

16.49 
15.67 
16.35 
16.57 

22.70 
22.54i 
23.71 
22.64 

2.09 
2.35 
2.00 
2.11 

0.29  MgO 

0.44  MgO 
0.41  MgO 

99.91 
99.93 
101.67 
100.05 

"Bourg  d'Osians" 
"Bourg  d'Osians" 
Arendal 
Arendal 

Scheerer26 
Stockar-Escher27 
Rammelsberg  2  8 
Scheerer*9 

The  Granite  Group 

A  number  of  Granites  examined  by  K.  H.  Schneer  may  be  expressed  by 

the  general  formula  : 

18  RO  •  6  R203  •  18  Si02  and  16  RO  •  6  R203  •  16  Si02 
as  may  be  ascertained  from  the  following  Table  : 


%                                                                       Molecules 

No. 

CaO 

FeO 

MnO 

A1.0, 

Fe20, 

SiOa 

H,0  ||   CaO 

FeO 

MnO 

A1.0, 

Fe,0,|siO,|H,O 

Theory 

33.25 

1.22 



6.92 

21.72 

36.89 

1 

33.59 

1.17 

— 

7.44 

20.94 

36.56 

— 

17.5 

0.5 

— 

2 

4 

18 

— 

Theory 

32.12 

1.82 

0.60 

6.88 

21.59 

36.68 

0.31 

2 

32.36 

1.91 

0.48 

7.35 

21.58 

36.33 

0.48 

17 

0.75 

0.25 

2 

4 

18 

0.5 

Theory 

32.12 

2.43 

— 

6.88 

21.59 

36.68 

0.30 

3 

31.51 

2.88 

— 

7.07 

22.51 

35.97 

0.25 

17 

1 

— 

2 

4 

18 

0.5 

Theory 

33.52 

1.25 

0.61 

12.39 

13.88 

37.73 

0.62 

4 

33.55 

1.68 

0.28 

11.99 

14.79 

37.53 

0.48 

17.25 

0.5 

0.25 

3.5 

2.5 

18 

1 

Theory 

34.22 

1.25 

— 

13.36 

12.57 

37.96 

0.64 

5 

34.01 

1.71 

0.54 

13.29 

13.01 

37.52 

0.53 

17.5 

0.5 

— 

3.75 

2.25 

18 

1 

Theory 

32.46 

3.85 

16.37 

8.56 

38.76 



6 

31.98 

4.46 

0.57 

16.29 

8.73 

37.96 

0.22 

16.25 

1.75 

— 

4.5 

1.5 

18 



Theory 

32.05 

2.74 

— 

13.72 

14.60 

36.89 



7 

32.73 

2.54 

— 

13.73 

14.03 

37.18 

— 

15 

1 

— 

3.75 

2.25 

16 

356 


THE   MESOLITES 


The 

The  following  analyses  of  the 

(a)  S  •  Al  -  Si  •  Al  •  S  =  6  A1203  •  15  Si02, 

(b)  Si  •  Al  •  Si  •  Al  •  Si  =  6  A1203  •  16  Si02, 

(a)  Mesolites  of  the  type 
Sf  •  Al  •  Si  •  Al  •  Si  =  6  A1203  •  15  Si02, 


Source 

Analyst 

1 

9  MO 

•2(6A12O3- 

15  SiO2) 

•36H2O 

9MO  =  3Na20 

•6CaO 

Antrimolite 
Bengune 

Thomson 

2 

11  MO 

•  2  (6  A12O3  • 

15SiO2) 

•26H2O 

HMO  =  5Na2O 

•6CaO 

Eisenach 

Luedecke 

(b)  Mesolites  of  the  type 
Si  -Al  -  Si  •  Al  •  Si  =  6  A1203  •  16  Si02 


Source 

Analyst 

3 

10  MO  -  2  (6  A12O3  •  16  SiO2)  30  H2O 

10MO=4Na2O-6CaO 

Sandy  Cove,  N.S. 

Marsh 

4 

11  MO  •  2  (6  A12O3  •  16  SiO2)  40  H2O 

HMO  =  5Na2O-6CaO 

Caranja  Isle 

Thomson 

5 

12  MO  •  2  (6  A12O3  •  16  SiO2)  24  H2O 

12MO  =  4Na2O-8CaO 

Harringtonite 

Thomson 

(c)  Mesolites  of  the  type 
Si  •  Al  •  Si  •  Al  -  Si  =  6  A1203  •  17  Si02 


Source 

Analyst 

6 

9  MO  •  2  (6  A12O3  •  17  SiO2)  •  32  H2O 

9  MO  =  2  Na2O  •  7  CaO     Iceland 

Fuchs  &  Gehlen 

7 

11  MO  •  2  (6  A12O3  •  17  SiO2)  •  30H2  O 

1  1  MO  =  4  Na2O  •  7  CaO     Iceland 

Breidenstein 

(d)  Mesolites  of  the  type 
Si  •  Al  •  Si  •  Al  •  Si  =  6  A1203  •  18  Si02 

1 

Source 

Analyst 

8 

12  MO-  2(6  A12O3  -  18  SiO2)  •  30H2O 

12MO  =  4  Na2O  •  8  CaO 

Niederkirchen 

Riegel 

9 
10 
11 
12 
13 

99                               99                                                                   99 
99                               99                                                                   99 
99                               99                                                                   99 
99                               99                                                                   99 

99                          9 
99                        9 
99                        9 
99                        9 
99                        9 

Tirol 
Antrimolite  / 
Bengune     \ 
Skye 
Skye 

Fuchs  &  Gehlen 
Heddle 
Heddle 
Heddle 
Heddle 

THE   MESOLITES 


357 


Mesolites 

Mesolites  conform  to  the  following  types  : 

(c)  Si  •  Al  •  Si  •  Al  •  Si  =  6  A1203 

(d)  Si  •  Ai  •  S*i  •  Al  •  Si  =  6  A1203 

or  the  general  formula 

m  MO  •  2  (6  A1203  •  15  Si02)  •  n  H20. 


17  SiO, 

18  SiO, 


SiO, 

Al,0, 

CaO 

Na,0 

H,0 

MgO 

Total 

Theory 
VII 

42.92 
43.47 

29.18 
30.26 

8.01 
7.50 

4.43 
4.10* 

15.46 
15.32 

0.19  FeO 

100.00 
100.94 

Theory 
II 

43.50 
43.83 

29.57 
29.04 

8.12 

7.84 

7.49 

7.80 

11.31 
11.75 

z 

100.00 
100.26 

or  the  general  formula 

m  MO  •  2  (6  A1203  •  16  Si02) 


nHoO. 


Si02 

A1,0S 

CaO 

NaaO 

H,0 

MgO 

Total 

Theory 
XXXII 

44.98 
45.39 

28.68 
28.09 

7.87 
7.55 

5.81 
5.28 

12.66 
12.71 

0.49  K2O 

100.00 
99.51 

Theory 
XXXIX 

42.58 
42.70 

27.14 
27.50 

7.45 
7.61 

6.87 
7.00 

15.96 
14.71 



100.00 
99.52 

Theory 
XI 

44.95 

44.84 

28.65 
28.48 

11.21 
10.68 

5.80 
5.56 

10.11 
10.28 

— 

100.00 
99.84 

or  the  general  formula 

m  MO  •  2  (6  R203  •  17  Si02) 


nHoO. 


SiO, 

Al,08 

CaO 

Na,0       |       H,0 

MgO 

Total 

Theory 
XXVI 

46.83 
46.58 

28.10 
27.57 

9.00 
9.10 

2.84 
3.64 

13.83 
13.17 

0.03 

100.00 
100.14 

Theory 
XXIII 

45.90 

45.78 

27.54 
27.53 

8.82 
9.00 

5.58 
5.03 

12.15 
12.30 

0.31  K,O 

100.00 
100.13 

or  the  general  formula 

m  MO  •  2  (6  A1203  •  18  SiO2)  •  n  H2O. 


SiO, 

Al,0, 

CaO 

Na,0 

H,0 

MgO 

Total 

Theory 

V 
VIII 
IX 
XIII 
XIV 

46.76 
46.65 
46.04 
47.07 
45.98 
46.70 
46.72 

26.49 
27.40 
27.00 
26.23 
26.18 
26.62 
26.70 

9.70 
9.26 
9.61 

9.88 
10.78 
9.08 
8.90 

5.37 
4.91 
5.20 
4.89 
4.54 
5.39 
5.40 

11.68 
12.00 
12.36 
12.24 
13.00 
12.83 
12.92 

— 

100.00 
100.22 
100.21 
100.31 
100.48 
100.63 
100.64 

*  Determined  by  Thomson  as  KaO. 


358 


THE   CLINTONITES 


Source 

Analyst 

12MO2(6A12OS-18  SiO2)-30H2O 

12MO  =  4Na2O-8CaO 

14 

Skye 

Heddle 

15 

NaalsjO 

Berzelius 

16 

NaalsjS 

Heddle 

17 

Naalsjo 

Fuchs  and  Gehlen 

18 

Naalsjo 

Durscher 

19 

StromO 

E.  E.  Schmid 

20 

Berufjord 

S.  v.  Waltershausen 

21 

Iceland 

Fuchs  and  Gehlen 

22 

Iceland 

Fuchs  and  Gehlen 

23 

Iceland 

E.  E.  Schmid 

24 

Iceland 

Lemberg 

25 

Port  George,  N.S. 

How 

26 

Port  George,  N.S. 

How 

27 

Cape  Blomidon 

Marsh 

28 

Atacama,  Chili 

Darapsky 

29 

14MO2(6  Al2O8-18SiO2H4H2O 

14MO  =  3Na20-llCaO 

Fritz  Island,  Pa. 

Sadtler 

The 

The  following  analyses  of  the  minerals  of  the 

=     5R,Oa-    6Si02, 
12  Si02, 
6  Si02, 
12  Si02, 

Si  =     6  R,0a  •  16  Si02, 
18  Si02. 


A. 
B. 
C. 
D. 
E. 
F. 

R 
R 

R 
R 

Si 

Si 

•&• 

•si- 

•Si- 
•Si- 
•R. 
•R. 

R 

Si 
R 
Si 

Si 

Si 

•R 

•  R 
•R 
-R 

2^3 

=  5R203 
=  6  R203 
-  6  R203 
6R203 
6R00, 


A.  Compounds  of  the  type 
R  .  Si  •  R  =  5  R203  •  6  Si02 


j 

Source 

Analyst 

1 

12M02  (5  Al203-6Si02)-12H20 

12MO  =  8FeO  -4MgO 

St.  Marcel 

Kobell 

2 

13MO-2  (5  Al2O3-6  SiO2)-9  H2O 

13MO  =  10FeO-2.5  MgO-0.5  MnO 

Leeds,  Canada 

Hunt 

B.  Compounds  of  the  type 
R  •  si  •  Si  •  R  =  5  R203  •  12  Si02 


Source 


Analyst 


3     13MO-2(5  Al2O3-12SiO2)-llH2o|       13MO  =  9.25FeO3.75  MgO  St.  Marcel       Damour 


THE   CLINTONITE   GROUP                             359 

SiO, 

Al,0, 

CaO 

Na2O 

H,0 

MgO 

Total 

Theory 

46.76 

26.49 

9.70 

5.37 

11.68 



100.00 

XV 

46.26 

26.48 

10.00 

4.98 

13.04 



100.76 

XVII 

46.80 

26.50 

9.87 

5.40 

12.30 



100.87 

XVIII              46.80 

26.46 

9.08 

5.14 

12.28 



99.76 

XIX                47.00 

26.13 

9.35 

5.47 

12.25 



100.20 

XX 

47.50 

26.10 

9.15 

4.57 

12.80 



100.12 

XXI 

47.40 

27.05 

9.16 

4.69 

12.69 

0.06 

101.05 

XXII 

46.41 

26.24 

9.68 

4.46 

13.76 

0.01 

100.97 

XXIV 

46.78 

25.66 

10.06 

4.79 

12.31 

99.60 

XXV 

47.46 

25.35 

10.04 

4.87 

12.41 



100.13 

XXVII 

47.13 

26.52 

10.36 

4.50 

12.59 



101.12 

XXVIII 

45.96 

26.69 

9.48 

5.09 

12.78 



100.00 

XXIX 

46.66 

26.48 

9.63 

4.83 

12.25 

— 

99.85 

XXX 

46.71 

26.68 

9.55 

5.68 

11.42 

— 

100.04 

XXXI 

45.89 

27.55 

9.13 

5.09 

12.79 

0.48  K20 

100.93 

XXXVI 

46.74 

25.99 

9.11 

5.23 

12.41 

— 

99.48 

Theory 

43.39 

24.59 

12.37 

3.73 

15.92 

_ 

100.00 

XXXIII 

43.29 

25.02 

12.15 

3.40 

16.01 

— 

99.87 

Glintonite  Group  * 

Clintonite  group  conform  to  the  following  types  : 


G.  Sl 


=  7.5  R0   •    6  Si0 


23 


H.  R  •  Si  •  R  •  SAi  •  R  =     8  R203  •  12  Si02, 

Jk 

J.   SI^-R  =     9R203-    6Si02, 

XR 
K.  R  •  Si  •  R  •  Si  •  R  =     9  R203  •  12  Si02. 

or  the  general  formula 

m  MO  •  2  (5  R203  •  6  Si02)  •  n  H20. 


SiO, 

A120, 

Fe,0, 

FeO 

MnO 

MgO 

CaO 

H,O             Total 

Theory 
IX 

26.74 
25.75 

37.89 
37.50 

~ 

21.40 
21.00 

z 

5.94 
6.20 

- 

8.03 
7.80 

100.00 

98.25 

Theory 
XXXI 

26.12 
26.30 

36.99 
37.10 

~ 

26.11 
25.92 

1.28 
0.93 

3.62 
3.66 

- 

5.88 
6.10 

100.00 
100.01 

or  the  general  formula 

m  MO  •  2  (5  R203  •  12.Si02)  •  n  H20. 


SiO, 


A1208 


Fe20, 


FeO 


MnO 


MgO 


CaO 


H20 


*  Known  in  Germany  as  the  Sprodglimmer  or  "brittle  micas." 


Total 


Theory 
XI 

26.23           37.27 
25.50           38.13 

— 

24.27 
23.58 

— 

5.11 
5.19 

— 

7.22 
6.90 

100.00 
99.30 

360 


THE   CLINTONITE   GROUP 


C.  Compounds  of  the  type 
R-  Si  •  R  =  6R203  •  6Si02 


Source 

4 

10  MO  •  2(6  B2O3  •  6  SiO2)  -  10  H2O 

10MO  =  7FeO-3MgO 
•  12  R203  =  8.75  A1203  •  3.25  Fe2O3 

Kossoibrod. 

5 
6 

11  MO  •  2(6  R203  •  6  Si02)  •  10  H2O 
11  MO  •  2(6  R2O3  •  6  Si02)  •  10  H2O 

11  MO  =  5  MgO  •  5.5  FeO  •  0.5  CaO 
•  12  R203  =  11.25  A1203  •  0.75  Fe2O3 

11  MO  =  4.75  MgO  •  0.25  MnO  •  5.5  FeO 
•  0.5  CaO  •  12  R2O3  =  11.5  A12O3  •  0.5  Fe2O3 

St.  Marcel 
Shetland 

7 

11  MO  -  2(6  A1203  •  6  Si02)-  12  H2O 

HMO  =  llFeO 

St.  Marcel. 

8 

12MO-2(6Al203-6Si02) 

12MO  =  12FeO 

Kossoibrod. 

9 

12  MO  •  2(6  A12O3  •  6  SiO2)-  10  H2O 

12  MO  =  1  1.5  FeO  •  0.5  H2O 

Gumuch-Dagh 

10 
11 

12  MO  •  2(6  A12O3-  6  SiO2)  •  10  H2O 
12  MO  •  2(6  A12O3-  6  SiO2)  -  12  H2O 

12  MO  =  10.5  FeO  •  1.5  MgO 
12  MO  =  7.75  FeO  •  4.25  MgO 

Grippe,  He  de 
Groix 

Zermatt. 

12 

12  MO  •  2(6  A12O3-  6  SiO2)  •  12  H2O 

12  MO  =  9.75  FeO  •  2.25  MgO 

Pregratten. 

13 

13  MO  •  2(6  A12O3-  6  SiO2)  •  12  H2O 

13  MO  =  11.75  FeO  •  0.75  MgO  •  0.25  MnO 
•  0.25  CaO 

Gumuch-Dagh. 

14 

13  MO  -  2(6  A1203-  6  SiO2)  •  12  H2O 

13  MO  =  11.  75  FeO  -0.75  MgO  -0.25  MnO 
•  0.25  CaO 

Gumuch-Dagh. 

15 

13  MO  •  2(6  A12O3-  6  SiO3)  •  12  H2O 

13  MO  =  7.5  FeO  •  0.5  MnO  •  5  MgO 

Shetland. 

16 

15  MO  -  2(6  A12O3-  6  SiO2)  •  11  H2O 

15MO  =  12FeO-3MgO 

Kossoibrod. 

D.  Compounds  of  the  type 
R  •  Si  •  Si  •  R  =6  R203  •  12  Si02 


Source 

Analyst 

17 

18 

10MO-2(6R2O3*12SiO2)- 
19MO-2(6Al203-12SiO2) 

8H20 
•14H20 

10  MO  =  6  FeO  •  3  MnO  •  0.5  MgO 
•  0.5  CaO  •  12  R2O3=11  A12O3  •  1  Fe2O3 

19  MO  =  15.5  FeO  •  3.5  MnO 

Lierneux 

Natic,Rh. 
Island 

Renard 
Jackson 

E.  Compounds  of  the  type 

Si  •  Al  •  Si  •  Al-  Si  =  6  A1203  •  16  Si02 


Source 


Analyst 


19    13MO-2(6Al2O3-16SiO2)-12H2O    13  MO  =  12.5  FeO  •  0.5  MgO 


Venasque 


Damour 


THE   CLINTONITE   GROUP 


361 


or  the  general  formula 

m  MO  •  2  (6  R203  •  6  Si02)  •  n  H20. 


Analyst 

|     Si08 

A1208 

Fea03 

FeO 

MnO 

MgO 

CaO 

H,0 

Total 

Hermann 

Theory 
XXVI 

24.52 
24.54 

30.39 
30.72 

17.71 

17.28 

17.17 
17.30 

, 

4.08 
3.75 

— 

6.13 
6.38 

100.00 
99.97 

Suida 

Theory 
X 

25.79 
26.03 

41.11 
42.33 

4.29 
4.09 

14.19 
14.32 

__ 

7.16 
7.30 

1.00 
0.35 

6.46 
6.56 

100.00 
100.98 

Heddle 

Theory 
XXI 

25.91 
25.36 

42.21 
41.74 

2.87 
3.90 

14.05 
13.93 

0.64 
0.92 

6.84 
6.82 

1.00 
0.90 

6.48 
6.57 

100.00 
100.14 

Delesse 

Theory 
VIII 

24.39 
24.10 

41.47 
40.71 

~ 

26.83 
27.10 

z 

~ 

— 

7.31 

7.24 

100.00 
99.15 

Erdmann 

Theory 
XXIV 

25.64 
24.96 

43.59 
43.83 

~ 

30.77 
31.21 

~ 

~ 

— 

~ 

100.00 
100.00 

Smith 

Theory 
XXVIII 

24.41 
24.10 

41.50 
39.80 



27.69 
27.55 

0.30 

(K2O+Na2O) 

6.40 
6.50 

100.00 
98.25 

Renard 

Theory 
XIII 

24.59 
24.90 

41.78 
40.36 

— 

25.45 
26.17 

___ 

2.05 
2.54 

- 

6.13 
6.23 

100.00 
100.23 

Damour 

Theory 
VI 

24.93 
24.40 

42.38 
42.80 

— 

19.33 
19.17 

— 

5.88 
6.17 

— 

7.48 
6.90 

100.00 
99.44 

A.  Sipocz 

Theory 
IV 

24.39 
24.90 

41.46 
40.99 

0.55 

23.78 
24.28 

— 

3.05 
3.33 

— 

7.32 

7.82 

100.00 
101.87 

L.  Smith 

Theory 
XXIX 

23.47 
23.94 

39.90 
39.52 

— 

27.58 
28.05 

0.58 
0.52 

0.98 
0.80 

0.46 
0.45 

7.03 

7.08 

100.00 
100.36 

L.  Smith 

Theory 
XXX 

23.47 
23.20 

39.90 
40.21 

— 

27.58 
27.25 

0.58 

0.98 
0.95 

0.46 
0.83 

7.03 
6.97 

100.00 
99.41 

Heddle 

Theory 
XX 

24.53 
24.47 

41.70 
41.34 

0.38 

18.40 
18.52 

1.21 

0.91 

6.81 
6.80 

0.30 

7.35 

6.98 

100.00 
99.70 

Kobell 

Theory 
XXVII 

23.03 
23.01 

39.15 
40.26 

— 

27.64 
27.40 

— 

3.84 
3.97 

— 

6.34 
6.34 

100.00 
100.98 

or  the  general  formula 

m  MO  •  2  (6  R203  •  12  Si02)  •  n  H20. 


SiO, 

A1203 

Fe208 

FeO 

MnO      |      MgO 

CaO 

H20 

Total 

Theory 
XVIII 

40.52 
40.55 

31.58 

30.80 

4.50 
3.82 

11.99 
12.46 

5.99 
6.51 

0.57 
0.45 

0.79 
1.29 

4.06 
4.12 

100.00 
100.00 

Theory 
XXXII 

33.64 
33.20 

28.59 
29.00 

— 

26.07 
25.93 

5.81 
6.00 

0.24 

__ 

5.89 
5.60 

100.00 
99.97 

or  the  general  formula 

m  MO  •  2  (6  R2O3  •  16  Si02)  •  n  H20. 


SiO, 


A120, 


Fe20, 


FeO 


MnO 


MgO 


CaO 


H20 


Total 


Theory 
XII 

44.87 
44.79 

28.60 
29.71 

— 

21.03 
20.75 

— 

0.46 
0.62 

— 

5.04     1  100.00 
4.93     1  100.80 

THE   CLINTONITE   GROUP 


F.  Compounds  of  the  type 
Si  •  ft  •  Si  •  ft  •  Si  =  6  R203  •  18  Si02 


Source 

Analyst 

20 

17  MO2(6  A12O8-18  SiO2)-16  H2O 

17MO  =  11.5FeO-5.5MnO 

Ottre 

Damour 

21 

17  MO2(6  A12O8-18  SiO2)-16  H2O 

17  MO-  11.5  FeO  -  5.5  MnO 

Ottrf 

Damour 

G.  Compounds  of  the  type 


i—  R  =  7.5R2O 
XR 


6Si0 


Source 


Analyst 


22     29  M02(7.5  R2O3-6  SiO2) 
•12H20 


=  19.75MgO-8.25CaO-lFeO 
15R203=14.5Al203-0.5Fe203    I 


Manzoni 


Sipocz 


H.  Compounds  of  the  type 
R  •  Si  •  R  •  Si  •  R  =  8  R203  •  12  Si02 


Source                    Analyst 

23 
24 

12MO-2(8R2O3-12SiO2) 
•12H20 

24  MO-2(8  A12O8-12  SiO2) 
•14H2O 

12MO  =  10FeO-2MgO 
•16R2O3=llAl203-5Fe208 

24  MO  =  24  FeO 

Natic,  Rh. 
Island 

Natic,  Rh. 
Island 

Hermann 
Whitney 

J.  Compounds  of  the  type 


Source 

Analyst 

25 
26 

30MO-2(9R2O3-6SiO2) 
•6H20 

30MO-2(9R2O3-6  SiO8) 
•6H20 

30MO  =  21.5MgO-8.5CaO 
•18  R2O3=17.5  A12O3-0.5  Fe2O8 

30  MO  =  21.  5  MgO-8.5  CaO 
•18R2O3  =  17.5Al2O3-0.5Fe2O3 

Ural 
Ural 

G.  Wagner 

O.  Schieffer- 
deeker 

K.  Compounds  of  the  type 
R  •  Si  •  6  •  Si  •  R  =  9  R203  •  12  Si02 


Source 

Analyst 

27 

28 
29 

20  MO-2(9  A12O3-12  SiO2) 
•24H20 

22  MO-2(9  A12O3-12  SiO2) 
•16H2O 

25MO-2(9Al2O3-12SiO2) 
•20  HaO 

20  MO  =  15.5  FeO-3.5  MgO 
•0.5  MnO  •  0.5  CaO 

22  MO  =  21  FeO-  1  MgO 
25  MO  =  19.5  FeO  •  5.5  MgO 

Kaisersberg 
Hetzschen 
Kossoibrod 

v.  Foullon 
Schroder 
Bonsdorff 

THE   CLINTONITE   GROUP 

or  the  general  formula 

m  MO  •  2  (6  R203  •  18  Si02)  •  n  H2O. 


363 


SiO, 

A1,0S 

Fe,0, 

FeO 

MnO 

Mgo 

CaO 

H,O 

Total 

Theory 
XIV 

44.16 
43.52 

25.04 
23.89 

__ 

16.93 
16.81 

7.98 
8.03 

___ 

— 

5.89 
5.63 

100.00 

97.88 

Theory 
XV 

44.16 
43.34 

25.04 
24.63 



16.93 
16.72 

7.98 
8.18 



z 

5.63 
5.66 

100.00 
98.53 

or  the  general  formula 


m  MO  •  2  (7.5  R2O3  •  6  SiO2)  •  n  H20. 


SiO, 

A1|0S 

Fe,0, 

FeO 

MnO 

MgO 

CaO 

H,0 

Total 

Theory 
11* 

18.95 
18.75 

38.94 
39.10 

2.10 
3.24 

1.89 
1.62 

— 

20.80 
20.46 

12.16 
12.14 

5.16 
5.35 

100.00 
100.66 

or  the  general  formula 

m  MO  •  2  (8  R203  •  12  Si02)  •  n  H2O. 


SiO, 

Al,0, 

Fe,0, 

FeO 

MnO 

MgO 

CaO 

H,0 

Total 

Theory 
XXXIV 

32.89 
32.68 

25.63 

26.38 

18.28 
18.95 

16.45 
16.17 

— 

1.82 
1.32 

— 

4.93 
4.50 

100.00 
100.00 

Theory 
XXXIII 

28.51 

28.27 

32.30 
32.16 

~ 

34.20 
33.72 

— 

0.13 

— 

4.99 
5.00 

100.00 
99.28 

or  the  general  formula 


m  MO  •  2  (9  R203  •  6  Si02)  •  n  H2O. 


SiO, 

Al,03 

Fe,0, 

FeO 

MnO 

MgO 

CaO 

H,0 

Total 

Theory 

17.87 

44.30 

1.99 

— 



21.35 

11.81 

2.68 

100.00 

Vllf 

17.42 

44.18 

3.53 

— 

— 

20.61 

11.95 

2.61 

100.30 

Theory 

17.87 

44.30 

1.99 

— 

— 

21.35 

11.81 

2.68 

100.00 

Vlllf 

17.70 

43.60 

2.90 

— 

— 

20.90 

11.50 

2.50 

99.10 

or  the  general  formula 

m  MO  •  2  (9  R203  •  12  Si02)  •  n  H2O. 

SiO, 

Al,0, 

Fe,0, 

FeO             MnO 

MgO 

CaO 

H,O 

Total 

Theory 

28.64 

36.52 

— 

22.20 

0.71 

2.78 

0.56 

8.59 

100.00 

II 

28.48 

36.86 

— 

21.88 

0.97 

2.80 

0.59 

8.09 

100.36 

Theory 

28.15 

35.89 



29.55 



0.78 



5.63 

100.00 

I    * 

28.04 

36.19 

— 

29.79 

— 

1.25 

0.20 

5.88 

100.35 

Theory 

27.38 

34.91 



26.69 



4.18 



6.84 

100.00 

XXII 

27.48 

35.57 

— 

27.05 

0.30 

4.29 

— 

6.95 

101.64 

*  Brandisite                                t  Xanthophyllite 

364 


THE   MICA   GROUP 


The 


The  following  analyses  of  the  minerals  of  the 

A.  Si  •  R  •  Si  =  3  R203  •  10  SiO2, 

B.  Si  -  R  •  Si  =  3  R203  •  12  Si02, 

/Si 

C.  R-Si        =  3  R203  •  15  Si02, 

D.  R-Si        =  3  R2O3  •  18  Si02, 

xsAi 

E.  R-Si-R  =  5R 


XSi 

A 


xsAi 

R-Si-R  =  5R203-    6Si02, 
A.  Mica  of  the  type 
Si  •  R  -  Si  =  3  R203  •  10  Si02 


Source 


20  MO 

•2(3R203- 
•6H2O 

10  Si02) 

20  MO 
•  6  R203 

=  16.5  MgO  • 
=  4.5A12O3- 

3.5  K2O 
1.5Fe2O3 

Biotite 

Chester, 
Mass. 

B.  Mica  of  the  type 
SAi  •  R  •  Si  =  3  R203  •  12  Si02 


Source 

6MO-2(3R203-12Si02) 

28MO-2(3R2O3-12SiO2) 
•6H20 

32  MO  •  2  (3  A12O3  •  12  SiO2) 
•2H2O 

6MO=1.5FeO-2MgO-2K20-0.5Na2O 
•6R203=5A1203-1V203 

28  MO  =  23  MgO  •  2  FeO  •  3  K2O 
•  6R2O3  =  5.5  A12O3  •  0.5  Fe2O3 

32  MO  =  26.5  MgO  •  2.5  K2O  •  3  Na2O 

Roscoe- 
lite 

Biotite 

Colorado 
Moravicza 

Edwards, 

N.S. 

C.  Mica  of  the  type 
/SI 
R~Si  =  3R203-  15Si02 
XSi 

Source 

115  MO  •  2  (3  R2O3  •  15  SiO2) 
•20  H20 

15  MO  =  15  MgO 
•  6  R2O3  =  3.5  Fe2O3  •  2.5  A12O3 

Biotite 

Vermont 

D.  Mica  of  the  type 


A 

R;—  Si  =  3  R203  •  18  Si02 

Source 

39  MO 
47  MO 

•2(3R203-18Si02) 
•6H20 

•  2  (3  A12O3  •  18  SiO.) 
•1H2O 

39  MO  =  32  MgO-  7  K2O 
•  6  R2O3  =  3  A12O3  •  3  Fe2O3 

47MO  =  3  FeO  •  17  MnO  •  21  MgO 
•3  CaO  •  3  K20 

Biotite 

Herschenberg 
Pajoberg 

THE   MICA   GROUP 


365 


Mica  Group 


Mica  group  conform  to  the  following  types  : 


F.  Si  •  R  •  R  •  Si 

=  5  R203 

•  12  Si02, 

G.  Si  -R  •  Si  •  R  •  Si 

-  5  R203 

•  18  Si02, 

H.  R  -  Si  •  R 

=  6  R203 

•    6Si02, 

J.  Si  •  R  -  R  •  Si 

=  6  R203 

•  10  Si02, 

K.  SAi  •  R  •  R  •  Si 

=  6  R203 

•  12  Si02, 

L.  Si  •  R  •  Si  •  R  •  Si 

=  6  R203  •  16  Si02, 

M.  Si  •  R  •  Si  •  R  •  Si 

=  6  R203 

•  18  Si02, 

N.  R  •  Si  •  R  •  Si  •  R 

=  9  R2O3  •  12  Si02, 

0.  Si  •  R  •  Si  •  R  •  Si  •  R  • 

§T  =  9  R20S 

•  20  Si02. 

of  the  general  formula 

m  MO  •  2  (3  R203  •  10  Si02 

)  •  n  H20. 

Analyst                                   SiO8 

A120,      Fe,08 

FeO         CaO         MgO         K2O 

Na2O        H2O        Total 

Pisani         Theory        39.95 

15.28       7.99 

—          —       21.97     10.95 

—         3.86     100.00 

CLXX        39.55 

15.95       7.80 

—       22.25     10.35 

—         4.10     100.00 

or  the  general  formula 


m  MO  •  2  (3  R203 


12  Si02)  •  n  H2O. 


Analyst 

SiOs 

Al,08 

Fe20, 

FeO 

CaO 

MgO 

K,0 

Na20 

H20 

Total 

Genth 

Theory- 

57.43 
56.74 

20.34 
19.62 

6.00V203 

7.78V203 

4.31 
3.84 



3.19 
2.63 

7.50 
8.11 

1.23 

0.94 



100.00 
99.66 

Rumpf 

Theory 
XLIV 

40.73 
40.16 

15.87 
15.79 

2.26 
2.53 

4.07 
4.12 

~ 

26.03 
26.15 

7.98 
7.64 

0.37 

3.06 
3.58 

100.00 
100.34 

Crawe 

Theory 
CLI 

40.35 
40.36 

17.15 
16.45 

— 

— 

— 

29.70 
29.55 

6.58 
7.23 

5.21 
4.94 

1.01 

0.95 

100.00 
99.48 

or  the  general  formula 

m  MO  •  2  (3  R203  •  15  Si02) 


nH20. 


Analyst 

Si02 

AljO8    j   Fe2O3 

FeO 

CaO 

MgO 

KaO 

Na20 

H2O 

Total 

Thomson 

Theory 
CLXXII 

50.34 
49.08 

7.13 

7.28 

15.67 
16.12 



— 

16.79 
16.96£ 

— 



10.07 
10.28 

100.00 
99.72 

or  the  general  formula 

m  MO  •  2  (3  R203  •  18  Si02)  •  n  H20. 


Analyst 

SiOa 

A1.0, 

Fe208 

FeO 

CaO 

MgO 

K2O 

NajO 

HSO 

Total 

Bromeis 

Theory 
XXIII 

43.27 
42.89 

1  6.13 
6.09 

9.62 
10.59 

— 

— 

25.64 
25.09 

13.18 
13.15 

0.36 

2.16 
2.30 

100.00 
100.47 

Igelstrom 

Theory 
CX 

38.63 
38.50 

10.94 
11.00 

— 

3.86 
3.78 

3.00 
3.20 

15.01 
15.01 

5.04 
5.51 

21.58MnO 
21.40MnO 

1.94 

1.60 

100.00 
100.00 

366 


THE   MICA    GROUP 


E.  Micas  of  the  type 
R  -Si  •  R  =  5R203-6Si02 


1 

Source 

8 

6.5  MO 

•  2  (5  A1203 
•6H20 

•  6  SiO2) 

6.5MO  =  4.5CaO 

1.5  FeO  -0.5  MgO 

Margarite 

Peekskill 

F.  Micas  of  the  type 

Si  •  R  •  R  •  Si  =  5  R203  •  12  Si02 


Source 

9 

3  MO 

•  2  (5  A1203 

•  12  SiO2) 

3  MO  =  1  FeO  •  0.5  MgO  •  1.5  K2O 

Pinitoid 

Weinheim 

•9H20 

10 

5  MO 

•2(5A1203 

•  12  SiO2) 

5  MO  =  1  MgO-  1.5K2O-2.5Na2O 

» 

Friebenreuth 

•9H20 

11 

6  MO 

•  2  (5  A1203 

•  12  SiO2) 

6  MO  =  2  MgO  •  3.5  K2O  •  0.5  Na2O 

Muscovite 

Unionville, 

•8H2O 

Pensylv. 

12 

6  MO 

•  2  (5  R2O3 

•  12  SiO2) 

6  MO  =  1  MgO  •  0.5  CaO  •  3.5  K2O 

Pinitoid 

Gleichinger 

•  11  H20 

•  1  Na2O  •  10  R2O3=9.5  A12O3  •  0.5Fe2O3 

Fels 

13 

7  MO 

•  2  (5  A12O3 

•  12  Si02) 

7  MO  =4  FeO  •  0.5  MgO  •  2  K2O 

„ 

Chemnitz 

•    7H20 

•  0.5  Na2O 

14 

20  MO 

.  2  (5  R2O3 

•  12  SiO2) 

20  MO  =  9.5  FeO  •  6.5  MgO  •  1.5  CaO 

Biotite 

Adamello 

— 

•  2.5Na2O  •  10R2O3=6  A12O3  •  4Fe2O3 

15 

22  MO 

•  2  (5  R203 

•  12  SiO2) 

22  MO  =  21  MgO  •  1  FeO 

?> 

Westchester 

•  48  H2O 

•  10  R2O3  =  8  A12O3  •  2  Fe2O3 

16 

23  MO 

•  2  (5  R2O3 

•  12  SiO2) 

23  MO  =  22  MgO  •  1  FeO 

M 

Westchester 

•  50  H2O 

•  10R203  =  8A1203-  2Fe203 

17 

24  MO 

•  2  (5  R2O3 

•  12  SiO2) 

24  MO  =  23  MgO  •  0.5  FeO  •  0.5  NiO 

M 

Culsagee 

•  44  H20 

•  10  R2O3  =  8.5  A12O3  •  1.5  Fe2O3 

Mine 

G.  Micas  of  the  type 

Si  •  R  •  Si  •  R"-  Sf  =  5  R203  •  18  Si02 

Source 

18 

4MO- 

2(5A1203- 

18  SiO2) 

4  MO  =  1  FeO  •  0.5  MgO  •  2  K2O 

Hygro- 

Rheinpfalz 

20H2O 

•0.5Na20 

philite 

19 

7  MO- 

2  (5  R2O3  • 

18  SiO2) 

7  MO  =  1  MnO  •  1  MgO  •  5K2O 

Muscovite 

Heidelberg 

• 

6H20 

•  10  R2O3  =  9.5  A12O3  •  0.5  Fe2O3 

20 

8  MO- 

2(5R203- 

18  SiO2) 

8  MO  =  5.5  MgO  •  0.5  CaO  •  2  K2O 

Gongylite 

Yli-Kitka- 

• 

12H2O 

•  10R2O3=8.5A12O3-  1.5Fe2O3 

jarvi 

21 

25  MO- 

2(5R203- 

18  SiO2) 

25MO  =  12.5FeO-5CaO-0.5MgO-4.5K,O 

Biotite 

Brevik 

• 

4H20 

•  2.5  Na2O 

•10R203  =  7Fe203-3Al203 

22 

34  MO- 

2  (5  R203  • 

18SiO2) 

34  MO  =25  MgO  •  4  FeO  •  5K2O 

Karosulik 

•  • 

12H20 

•  10R203=8.5  A1203  -  1.5Fe203 

23 

40  MO- 

2(5R203- 

18  SiO2) 

40  MO  =  11.5  FeO  •  23  MgO  •  5  K2O 

M 

Tschebarkul 

2H2O 

•  0.5  Na2O 

•10R2O3  =  8Al203-2Fe2O3 

24 

50  MO  - 

2  (5  A12O3  • 
34H20 

18  SiO2) 

50  MO  =  41.5  MgO  •  8.5  FeO 

» 

Milbury 

THE   MICA   GROUP 

or  the  general  formula 

m  MO  •  2  (5  R203  •  6  Si02)  •  n  H20. 


367 


Analyst 


Si02        A1403       Fea03        FeO 


CaO 


MgO        KaO        NazO        H,0         Total 


Chatard 

Theory 
XVIII 

32.32 
32.73 

45.78 
46.58 

— 

4.84 
5.12 

11.32 
11.04 

0.90 
1.00 

— 

— 

4.84  |  100.00 
4.49  1100.96 

or  the  general  formula 

m  MO  •  2  (5  R203  •  12  Si02)  •  n  H20. 


Analyst 

Si02 

A1203 

Fea03 

FeO 

CaO 

MgO 

K80 

NaaO 

HaO    |    Total 

Cohen 

Theory 
III 

50.44 
50.82 

35.72 
35.93 

~ 

2.53 
2.92 

~ 

0.70 
0.41 

4.93 
4.13 

0.08 

5.67 
5.68 

100.00 
99.99 

v.  Ammon 

Theory 
IV 

48.68 
49.08 

34.49 
34.75 

~ 

z 

~ 

1.33 
0.85 

4.78 
5.40 

5.24 
5.30 

5.48 
5.35 

100.00 
100.73 

Chatard 

Theory 
C 

47.30 
46.60 

33.50 
32.39 

2.54 

~ 

~ 

2.63 
2.01 

10.81 
10.39 

1.02 
0.54 

4.73 

4.81 

100.00 
99.28 

Hilger 
Knop 

Theory 
V 

Theory 

45.92 
45.24 

46.26 

47.77 

30.90 
29.96 

32.76 
32.65 

2.55 
3.16 

0.32P205 

9.25 
8.94 

0.89 
1.44 

1.27 
1.15 

0.64 
0.49 

10.17 
10.13 

6.04 
5.86 

1.98 
2.15 

0.99 
1.50 

6.32 
6.24 

4.06 
4.19 

100.00 
99.79 

100.00 
101.00 

Baltzer 

Theory 
LIII 

36.41 
36.43 

15.47 
14.40 

16.19 
16.71 

17.30 
17.40 

2.12 
1.66 

6.57 

6.87 

5.94 
5.54 

0.03 

— 

100.00 
99.04 

Konig 

Theory 
CXXXVIII 

33.22 
33.35 

18.81 
17.78 

7.38 
7.32 

1.66 
2.11 

— 

19.01 
19.26 

__ 

___ 

19.92 
19.87 

100.00 
99.69 

Konig 

Theory 
CXL 

32.52 
33.03 

18.43 
17.38 

7.23 
7.41 

1.63 
1.44 

- 

19.87 
20.16 

— 

— 

20.32 
20.90 

100.00 
100.32 

Chatard 

Theory 
CXXXII 

33.24 
34.00 

20.01 
20.36 

5.54 
4.91 

0.82 
0.42 

— 

21.23 
21.71 

0.86NiO 
0.57N1O 

— 

18.30 
18.50 

100.00 
100.47 

or  the  general  formula 

m  MO  •  2  (5  R203  •  18  Si02)  .  n  H20. 


Analyst 

Si02 

Ala08 

Fe203 

FeO 

CaO 

MgO 

K80 

Na,0 

H,0 

Total 

Sch  wager 

Theory 
II 

56.08 
56.64 

26.49 
26.68 

— 

1.87 
1.68 

0.22 

0.52 
0.29 

4.88 
5.33 

0.80 
0.64 

9.36 
9.13 

100.00 
100.73 

Knop 

Theory 

55.41 
56.37 

24.86 
24.22 

2.05 
2.09 

1.82MnO 
2.5  MnO 

~ 

1.03 
0.83 

12.06 
12.61 

0.03 

2.77 
2.41 

100.00 
101.06 

Thoreld 

Theory 

55.11 
55.22 

22.12 
21.80 

6.12 

4.80 

0.32MnO 

0.72 
0.77 

5.62 
5.90 

4.80 
4.46 

0.45 

5.51 
5.77 

100.00 
99.49 

Muller 

Theory 
XCIX 

39.59 
39.38 

5.60 
6.65 

20.53 
19.89 

16.50 
16.43 

5.13 
5.47 

0.73 
0.56 

7.75 

7.86 

2.84 
2.81 

1.33 
1.39 

100.00 
100.44 

Kobell 

Theory 
CLXXVII 

41.21 
41.00 

16.55 

16.88 

4.58 
4.50 

5.49 
5.05 

— 

19.08 
18.86 

8.97 
8.76 



4.12 
4.30 

100.00 
99.35 

Zellner 

Theory 

cxx 

38.72 
38.49 

14.63 
14.43 

5.73 
5.44 

14.85 
14.75 

, 

16.50 
16.35 

8.42 
8.12 

0.50 
0.53 

0.65 
0.89 

100.00 
99.00 

Crossley 

Theory 
CLXXI 

35.62 
35.74 

16.82 
16.42 

— 

10.09 
10.02 

— 

27.38 
27.44 

— 

— 

10.09 
10.30 

100.00 
99.92 

368 


THE   MICA   GROUP 


H.  Micas  of  the  type 
R  •  Si  •  R  =  6  R«0,  •  6  SiO 


Source 

25 

1MO- 

2(6A12O3- 

6  SiO2)  • 

2H2O 

1  MO  =  0.25  MgO  •  0.25  K2O 
•  0.25  Na20-  0.25  H20 

Lesleyite 



26 

2  MO- 

2(6A12O8 

6  SiO2) 

•5H20 

2  MO  =  1.75  K2O-0.25  H2O 

N 

— 

27 

6MO- 

2(6R203- 

6  SiO2)  • 

7H20 

6MO  =  5CaO-  1  Na2O 
•12  R2O3=  11.75  Al2O3-0.25Fe2O3 

Margarite 

Nikaria 

J.  Micas  of  the  type 
Si  •  R  •  R  •  Si  =  6  R203  •  10  Si02 


Source 


28 


29  4  MO  •  2  (6  A12O3  •  10  SiO2) .  10  H2O 


30 


31 


4  MO  •  2(6  A12O3  •  10  SiO2)  •  10  H2O 


4  MO  •  2  (6  A1203  •  10  Si02)  •  10  H2O 
4  MO  •  2  (6  A12O3  •  10  SiO2)  •  10  H2O 


4  MO  =  0.5  CaO  •  0.5  MgO  -1K2O 
•  2  Na2O 

4  MO =0.5  CaO  •  0.5  MgO  •  1K2O 
.  2  Na2O 

4  MO=0.5  CaO  •  0.5  MgO  •  1K2O 
•2Na20 

4  MO=0.5  CaO  •  0.5  MgO  •  1K2O 
•2Na,0 


Muscovite 


Ebendaher 


K.  Micas  of  the  type 
Si  •  R  •  R  •  Si  =  6  R202  •  12  SiO, 


Source 

32 
33 

4  MO  •  2  (6  R2O3  •  12  SiO2) 
4  MO  •  2  (6  A1203  •  12  SiO2)  •  8  H2O 

4MO  =  4K2O 
12  R2O3  =  9.5  Al2O3-2.5Fe2O3 

4  MO  =0.5  CaO  •  0.5MgO-3Na2O 

Micarelle 
Paragonite 

M.  Campione 

34 

»               »>               »               » 

4MO  =  lK2O-3Na2O 

n 

M.  Campione 

35 

4  MO  •  2  (6  A12O3  •  12  SiO2)  •  9  H2O 

4  MO  =  3.5  K2O  •  0.5  Na2O 

Muscovite 

Unionville 

30 

»>               »»               »               » 

4  MO  =  3.5  K2O  •  0.5  Na2O 

n 

" 

37 

>»              »              »               »> 

4  MO  =  3.5  K2O  •  0.5  Na2O 

„ 

Wiesenthal 

38 

„ 

4  MO  =  0.5  K2O  •  3.5  Na2O 

Paragonite 

Borgofrance 

30 

»               »              »»              » 

4  MO  =0.5  K2O  •  3.5  Na2O 

n 

Colle  Blasier 

40 

»               >»               »               »> 

4  MO  =  0.5MgO-3K2O-0.5Na2O 

Muscovite 

Culsagee 
Mine 

41 

4  MO  •  2  (6  A1203  •  12  SiO2)  •  10^,0 

4MO  =  4K2O 

» 

Vallee  de 
1'Evel 

42 

5  MO  •  2(6  A12O3  •  12  SiO2)  •  8  H2O 

5MO  =  0.5MgO-0.5CaO-0.5FeO 
•  3  K2O  •  0.5  Na2O 

» 

Bengal 

THE   MICA   GROUP 


of  the  general  formula 
m  MO  •  2  (6  R203  •  6  Si02) 


nH20. 


Analyst 

Si02 

A1203 

Fe203 

FeO 

CaO 

MgO 

K80 

Na20 

H20 

Total 

Genth 

Theory 

35.42 

60.19 

— 

— 

— 

0.51 

0.76 

1.13 

1.99 

100.00 

XI 

35.68 

60.29 

0.72 

— 

— 

0.29 

0.41 

0.96 

1.78 

100,13 

Sharpless 

Theory 

32.69 

55.56 

— 

— 

— 



7.46 



4.29 

100.00 

V 

33.59 

55.41 

— 

— 

— 

— 

7.43 

— 

4.30 

100.73 

Smith 

Theory 

29.65 

49.39 

1.65 

— 

11.55 





2.55 

5.19 

100.00 

IX 

30.22 

49.67 

1.33 

— 

11.57 

Trace 

— 

2.31 

5.12 

100.22 

or  the  general  formula 

m  MO  •  2  (6  R203  •  10  Si02)  •  n  H20. 


Analyst 

Si02 

A1208 

Fe20, 

FeO 

CaO 

MgO 

K80 

NaaO 

H,0 

Total 

Smith  &  Brush 

Theory 
CII 

41.82 
40.29 

42.65 
43.00 

1.30 

— 

0.98 
1.01 

0.69 
0.62 

3.27 
3.94 

4.32 
5.16 

6.27 
5.00 

100.00 
100.32 

»»                » 

Theory 

cm 

41.82 
39.64 

42.65 
42.40 

1.60 

~ 

0.98 
1.00 

0.69 
0.70 

3.27 
3.94 

4.32 
5.16 

6.27 
5.08 

100.00 
99.52 

»                »> 

Theory 
CIV 

41.82 
40.21 

42.65 
41.40 

1.30 

~ 

0.98 
1.11 

0.69 
0.70 

3.27 
3.25 

4.32 
4.26 

6.27 
6.23 

100.00 
99.21 

»                » 

Theory 
CV 

41.82 
40.96 

42.65 
41.40 

1.30 

~ 

0.98 
1.11 

0.69 
0.70 

3.27 
3.25 

4.32 
4.26 

6.27 
6.23 

100.00 
99.21 

or  the  general  formula 

m  MO  •  2  (6  R203  •  12  Si02)  •  n  H20. 


Analyst 

SiO2 

A1203 

Fe2Os 

FeO 

CaO 

MgO 

K2O 

Na,0 

H20 

Total 

Massalin 

Theory 

45.21 

30.42 

12.56 





11.81 



_ 

_ 

100.00 

I 

45.00 

30.00 

12.60 

— 

— 

12.40 

— 

— 

— 

100.00 

Rammelsberg 

Theory 

47.34 

40.24 





0.92 

0.66 



6.11 

4.73 

100.00 

II 

46.81 

40.06 

Trace 

— 

1.26 

0.65 

Trace 

6.40 

4.82 

100.00 

Lemberg 

Theory 

46.65 

39.64 









3.04 

6.01 

4.66 

100.00 

IV 

46.17 

40.29 

— 

— 

— 

— 

3.09 

5.53 

4.92 

100.00 

Genth 

Theory 

45.21 

38.42 









10.32 

0.97 

5.08 

100.00 

XCVII 

45.86 

37.61 

0.59 

— 

0.31 

0.55 

10.40 

0.80 

4.74 

100.90 

Konig 

Theory 

45.21 

38.42 









10.32 

0.97 

5.08 

100.00 

XCVIII 

45.73 

37.10 

1.30 

— 

— 

0.34 

10.50 

0.88 

4.48 

100.33 

Sauer 

Theory 

45.21 

38.42 









10.32 

0.97 

5.08 

100.00 

XVIII 

45.71 

38.64 

— 

— 

— 

— 

9.53 

0.90 

5.17 

100.00 

Cossa 

Theory 

46.61 

39.61 

— 







1.52 

7.02 

5.24 

100.00 

VII 

46.67 

39.02 

2.01 

— 

— 

— 

1.36 

6.37 

4.91 

100.34 

»» 

Theory 

46.61 

39.61 

— 







1.52 

7.02 

5.24 

100.00 

VIII 

46.68 

39.88 

1.06 

— 

— 

— 

0.84 

6.91 

5.08 

100.45 

K6nig 

Theory 

45.69 

38.75 

— 





0.63 

8.92 

0.98 

5.13 

100.00 

XC 

45.62 

35.93 

2.93  = 

1.87A1203 

— 

0.34 

9.40 

0.71 

4.93 

99.86 

Delesse 

Theory 

44.72 

38.01 

— 

— 





11.68 



5.95 

100.00 

XLVIII 

45.22 

37.85 

Trace 

— 

— 

— 

11.20 

— 

5.25 

99.52 

Blau 

Theory 

44.93 

38.19 



1.12 

0.87 

0.62 

8.80 

0.96 

4.49 

100.00 

LXXXI 

45.57 

36.72 

0.95 

1.28 

0.21 

0.38 

8.81 

0.62 

5.05 

99.93 

2    B 


370 


THE   MICA  GROUP 


Source 


5  MO  •  2(6  A12O3  •  12  SiO2)  •  8  H2O 


7  MO  •  2(6  A12O3  •  12  Si03)  •  12  H2O 


=  0.5MgO-0.5CaO-0.5FeO 
•3  K2O-0.5  Na2O 

=  4K2O-lMgO 
12  R2O3=11  A12O3-1  Fe2O3 

=  0.5CaO-2.5MgO-3.5K2O 
•0.5  Na2O 


Muscovite 


East  Indies 

Horrsjoberg 

Maryland 


Si 


Si 


L.  Micas  of  the  type 
R  •  Si  =  6  R2O3  •  16  SiO2 


Source 

46 

4  MO  •  2(6  A12O3  • 

16SiO2) 

4  MO  =  0.5  FeO  •  3  K2O  •  0.5  Na2O 

Killinite 

Branchville 

•8H2O 

47 

5MO-2(6A12O3- 

16  Si02) 

5  MO  =  1.5  FeO  •  1  CaO  •  0.5  Li2O 

,, 

Killiney 

•8H2O 

•2K20 

Hill 

48 

5  MO  •  2(6  R2O3  - 
•9H20 

16  SiO2) 

5  MO  =  1  MgO  •  2  K20  -  2  Na2O 
12  R2O3=  10  A12O3  •  2  Fe2O3 

Muscovite 

Oravicza 

49 

6MO-2(6R2O3- 

16  SiO2) 

6  MO  =  0.5  MgO  •  5.5  K2O 

tf 

Striegau 

•10H20 

12R2O3=lFe203'llAl203 

50 

6  MO  •  2(6  A12O3  • 
•  22  H20 

16SiO2) 

6  MO  =  1.5  FeO  •  0.5  CaO  •  1  MgO 
•3K20 

Killinite 

Killiney 
Hill 

51 

6MO-2(6A12O3- 

16SiO2) 

6MO  =  1.5FeO  •  1.1  MnO  •  0.5  CaO 

t» 

»>         »» 

•  22  H20 

•0.5  MgO-  2.5  K20 

52 

7  MO  •  2(6  A1203  • 
•10H20 

16  SiO2) 

7  MO  =0.5  FeO  •  2.5  MgO  -  4  K2O 

Muscovite 

Grube  Him- 
melsfiirst 

53 

7  MO  •  2(6  A12O3  • 

16  SiO2) 

7  MO  =  1.5  FeO  •  0.5  CaO  •  2  MgO 

Hygro- 

— 

•  20  H2O 

•  2  K2O  •  1  Na2O 

philite 

54 

8  MO  •  2(6  A12O3  • 

16  SiO2) 

8  MO  =  2  FeO  •  1  CaO  •  0.5  MgO 

n 

— 

•  20  H2O 

-  0.25  K2O  -  1  Na2O 

55 

12MO-2(6A12O3- 

16SiO2) 

12  MO  =  1  CaO  •  3.5  MgO  •  4.5  K2O 

Paragonite 

Fenestrelle 

-6H2O 

3Na20 

56 

26MO-2(6R2O3- 

16SiO2) 

26  MO  =0.5  CaO  •  18.5  MgO  •  7  K2O 

Biotite 

Zillerthal 

•3H20 

12R2O3=8Al203-4Fe2O3 

57 

27  MO  •  2(6  R2O3  - 

16  SiO2) 

27  MO  =  1  FeO  •  0.5  CaO  •  25.5  MgO 

»» 

West- 

•40H2O 

12  R203=8.5  A1203  -  3.5  Fe2O3 

chester 

58 

29MO-2(6R203- 

16  SiO2) 

29  MO  =  1.5  FeO  -  27.5  MgO 

,, 

„ 

•  60  H2O 

12R203=9Al203-3Fe2O3 

59 

30MO-2(6R2O3- 

16  SiO2) 

30  MO  =  1  1  FeO  -12.5  MgO  •  5  K2O 

>» 

Renchthal 

•6H20 

•  1.5Na20  -  12  R203=10  A12O3  •  2  Fe2O3 

60 

30MO-2(6A1203- 

16  SiO2) 

30  MO  =  21.5  FeO  -  8.5  MgO 

»> 

Monroe 

•  28  H20 

61 

32MO-2(6R2O3- 

16  SiO2) 

32  MO=31.5  MgO  •  0.5  FeO 

M 

Calsagee 

•32H20 

12  R203=  10  A12O3  -  2  Fe2O3 

Mine 

62 

32MO-2(6R2O3- 

16  SiOa) 

32  MO  =31.  5  MgO  •  0.5  FeO 

JM 

„ 

•64H20 

12  R2O3=  10  AI2O3  •  2  Fe2O3 

63 

34MO-2(6R203- 

16SiO2) 

34  MO  =  33.5  MgO  •  0.5  FeO 

» 

ft 

•60$20 

12  R2O3=  10  A12O3  •  2  Fe2O3 

64 

35  MO  •  2(6  AlaO3  • 

16  Si02) 

35MO  =  21.5FeO-lCaO-11.5MgO 

»» 

Rio  de 

•  34  H20 

•1K20 

Janeiro 

THE   MICA  GROUP 


371 


Analyst 

SiO, 

Al,0, 

Fe,0,  |         FeO          |   CaO 

MgO 

K,0 

Na,O 

H,0 

Total 

Sipocz 

Theory 
LXXXII 

44.93 
45.71 

38.19 
36.57 

1.19 

1.12 
1.07 

0.87 
0.46 

0.62 
0.71 

8.80 
9.22 

0.96 
0.70 

4.49 
4.83 

100.00 
100.67 

Igelstrom 

Theory 
LXXIII 

43.88 
43.41 

34.18 
35.17 

4.87 
4.62 

. 

— 

1.22 
1.40 

11.46 
10.90 

~ 

4.39 
4.50 

100.00 
100.00 

Chatard 

Theory 
XCIII 

42.75 
42.21 

36.35 
34.55 

1.03 

2.03Cr2O3 

0.83 
0.47 

2.96 
3.13 

9.77 
9.16 

0.92 
0.82 

6.42 
6.77 

100.00 
100.17 

or  the  general  formula 

m  MO  •  2  (6  R203  -  16  Si02)  •  n  H20. 


Analyst 

SiO, 

Al,0, 

Fea03      |   FeO 

CaO 

MgO 

K,0 

Na,0 

H,0 

Total 

Dewey 

Theory 

52.79 

33.65 

— 

0.99 

— 

— 

7.76 

0.86 

3.95 

100.00 

VII 

53.47 

32.36 

0.79 

0.42 

0.17 

0.72  MnO 

7.68 

0.44 

4.07 

100.16 

Mallet 

Theory 

52.53 

33.49 

— 

2.95 

1.53 

— 

5.14 

0.42  Li2O 

3.94 

100.00 

III 

52.89 

33.24 

— 

3.27 

1.45 

— 

4.94 

0.46  Li2O 

3.67 

99.92 

Kjerulf 

Theory 

50.88 

27.03 

8.47 

— 

— 

1.06 

4.98 

3.29 

4.29 

100.00 

XXIV 

50.88 

26.69 

8.48 

— 

— 

1.19 

4.52 

2.72 

4.19 

98.67 

Riepe 

Theory 

48.99 

28.62 

4.08 

— 

— 

0.52 

13.20 

— 

4.59 

100.00 

XIX 

49.27 

28.69 

2.89 

— 

— 

0.42 

13.91 

— 

4.77 

99.95 

Lehunt 

Theory 

48.03 

30.62 

— 

?2.70 

0.70 

1.00 

7.05 

— 

9.90 

100.00 

I 

49.08 

30.60 

— 

2.27 

0.68 

1.08 

6.72 

— 

10.00 

100.43 

Blythe 

Theory 

47.98 

30.59 

1.77MnO 

2.69 

0.70 

0.50 

5.88 

— 

9.89 

100.00 

II 

47.93 

31.04 

1.26MnO 

2.33 

0.72 

0.46 

6.06 

— 

10.00 

99.80 

Scheerer 

Theory 

50.05 

31.91 

___ 

0.94 

__ 

2.61 

9.80 



4.69 

100.00 

XV 

47.84 

29.98 

2.91 

1.12 

0.05 

2.02 

9.48 

1.72  TiOa 

4.40 

99.52 

Killing 

Theory 

48.36 

30.81 

— 

2.72 

0.71 

2.02 

4.73 

1.56 

9.07 

100.00 

IV 

48.60 

32.82 

— 

2.76 

0.84 

2.37 

4.08 

1.32 

8.83 

101.62 

Laspeyres 

Theory 

47.28 

30.14 



3.54 

1.38 

1.47 

5.79 

1.53 

8.87 

100.00 

I 

48.42 

32.06 

— 

3.26 

1.15 

1.72 

5.67 

1.36 

9.02 

102.66 

Cossa 

Theory 

47.33 

30.17 



— 

1.38 

3.45 

10.43 

4.58 

2.66 

100.00 

IX 

47.96 

31.03 

— 

— 

1.07 

3.42 

10.44 

4.08 

2.41 

100.41 

Varren- 

Theory 

39.54 

16.81 

13.17 

__ 

0.58 

15.24 

13.55 



1.11 

100.00 

trapp 

XLVI 

39.85 

16.07 

13.21 

— 

0.42 

15.60 

13.68 

— 

1.17 

100.00 

Brush 

Theory 

37.02 

16.72 

10.80 

1.39 

0.54 

19.65 

— 

— 

13.88 

100.00 

CXXXVII 

37.10 

17.57 

10.54 

1.26 

0.56 

19.65 

0.43 

— 

13.76 

100.87 

Chatard 

Theory 

34.25 

16.37 

8.56 

1.93 

__ 

19.62 





19.27 

100.00 

CXXXIX 

34.40 

16.63 

8.00 

2.11 

— 

19.30 

— 

— 

19.03 

99.47 

Killing 

Theory 

36.73 

19.52 

6.12 

15.23 

_  _ 

9.57 

8.99 

1.77 

2.07 

100.00 

VI 

37.67 

18.79 

6.48 

15.28 

— 

9.72 

8.93 

1-92 

2.33 

101.12 

Pisani 

Theory 

34.69 

22.11 



27.96 

__ 

6.14 



— 

9.10 

100.00 

CLXIV 

34.98 

21.88 

— 

28.44 

— 

6.24 

— 

— 

9.22 

100.76 

Cooke 

Theory 

37.42 

19.87 

6.23 

0.70 

__ 

24.55 





11.33 

100.00 

CXXXIII 

37.58 

19.73 

5.95 

0.58 

— 

25.13 

— 

— 

11.09 

100.06 

Chatard 

Theory 

33.64 

17.88 

5.59 

0.63 

_ 

22.08 





20.18 

100.00 

CXXXI 

33.77 

17.56 

5.61 

0.50 

— 

22.48 

— 

— 

20.30 

100.22 

Konig 

Theory 

33.59 

17.85 

5.60 

0.63 

_  _ 

23.45 





18.88 

100.00 

cxxx 

33.93 

17.38 

5.42 

0.50 

23.43 

0.35  NiO 

— 

19.17 

100.18 

C.v.Hauer 

Theory 

32.47 

20.70 



26.17 

0.95 

7.77 

1.59 

— 

10.35 

100.00 

cxxv 

32.33 

20.47 

— 

,26.25 

0.85 

7.75 

2.02 

— 

10.33 

100.00 

372 


THE   MICA   GROUP 


M.  Micas  of  the  type 
Si  •  R  •  Si  •  R  •  Si  =  6  R203  •  18  Si02 


Source 

65 

5  MO 

•2(6R203- 

18SiO2) 

5  MO  =  0.5  CaO  •  4.5  K2O 

Micarelle 

— 

•3H20 

12  R203  =  9.5  Al203-2  Fe2O3-0.5  Mn2O3 

66 

6  MO 

•  2(6  A12O3  • 

18  SiO2) 

6  M0  =  2  FeO  •  1.5  MgO  •  2  K2O 

Killinite 

Killiney 

•18H20 

•  0.5  Na20 

Hill 

67 

6  MO 

•  2(6  A12O3  • 

18SiO2) 

6  M0  =  1.5  FeO  •  1  MgO  •  3  K2O 

n 

Dalkey 

•19H2O 

•  0.5  Na2O 

68 

7  MO 

•  2(6  A12O3  • 

18SiO2) 

7  MO=0.5  FeO  •  3.5  MgO  •  3  K2O 

Muscovite 

Tamsweg 

•  10H2O 

69 

26  MO 

•  2(6  R2O3  • 

18Si02) 

26  MO  =  12  FeO  •  5.5  CaO-  5  K2O 

Biotite 

Brevik 

•4H2O 

•3.5  Na2O;  12  R2O3  =  9.5  Al2O3-2.5Fe2O3 

70 

29  MO 

•2(6R203- 

18  SiO2) 

29  MO  =  23.5  MgO  •  4.5  K2O  •  1  Na2O 

M 

Laacher 

12  R2O3  =  8.5  A12O3  •  3.5  Fe2O3 

See 

71 

36  MO 

•2(6R2O3- 

18  SiO2) 

36  MO  =  35.5  MgO  •  0.5  FeO 

» 

Magnet 

•86H20 

12  R2O3=9.5  A12O3  •  2.5  Fe2O3 

72 

37  MO 

•2(6A1203- 

18SiO2) 

37  MO  =  15.5  FeO  •  2  MnO  •  19.5  MgO 

»» 

Prefiburg 

•12H20 

73 

39  MO 

•2(6R203- 

18Si02) 

39  M0  =  33  MgO  •  1  CaO  •  5  K2O 

M 

Vesuvius 

•2H20 

12  R2O3  =  9  A12O3  •  3  Fe2O3 

N.  Micas  of  the  type 
R  •  Si  •  R  •  Si  •  R  =  9  R203  •  12  Si02 


1 

Source 

74 

12MO- 

2(9  A12O3 
12H20 

•  12  SiO2) 

12  M0  =  2  FeO  •  0.5  MnO  •  9.5  CaO 

Margarite 

Tokowaja 

75 
76 

29  MO- 
29  MO- 

2(9  R203 
10H2O 

2(9R203 
10H2O 

•  12  SiO2) 
•  12  Si02) 

29  MO  =  1  .5  FeO  •  21  MgO  •  1.5  K2O 
•  5  Na2O  ;  18  R2O3  =  17.5  Al2O3-0.5Fe2O3 

29  MO  =  1.5  FeO  •  21  MgO  •  1.5  K2O 
.  5  Na2O  ;  18  R2O3=  17.5  A12O3-0.5  Fe2O3 

Willcoxite 

Shooting 
Creek 

Cullakenee 
Mine 

0.  Micas  of  the  type 
Si  •  R  *  Si  •  R  •  Si  •  R  •  Si  =  9  R203  •  20  Si02 


1 

Source 

77 

4MO- 

2(9  R2O3  • 
•24H20 

20  SiO2) 

4  MO  =  0.5  FeO  •  0.5  MgO  •  2.5  K2O 
•  0.5  CaO;  18  R2O3=  17.5  Al2O3-0.5Fe2O3 

Hygro- 
philite 

Nil  St. 
Vincent 

78 

6MO- 

2(9  R203  • 
•18H2O 

20  Si02) 

6MO  =  5.5K2O-0.5H2O 
18R203  =  17Al203-lFe203 

Lesleyite 

— 

79 

7MO- 

2(9A1203- 

20  SiO2) 

7  MO  =  2.5  CaO  •  3  MgO  •  1.5  K2O 

Muscovite 

Dobrawa 

•  15  H20 

80 

8MO- 

2(9R203- 
•16H20 

20  SiO2) 

8MO  =  lMgO-7K2O 
18  R2O3  =  16  A12O3  •  2  Fe2O3 

" 

Mt.Leinster 
Carlow 

81 

9MO- 

2(9  R2O3  • 

20  SiO2) 

9  MO  =  1  CaO  -  2  MgO  •  4  K2O  •  2  Na2O 

„ 

Botriphinie 

•  16  H20 

18  R2O3=  15.5  A12O3  •  2.5  Fe2O3 

82 

9MO- 

2(9R203- 

20  Si02) 

9  MO  =  1  CaO  •  2  MgO  -  4  K2O  •  2  Na2O 

n 

Vanlup 

•16H20 

18  R2O3=  15.5  A12O3  •  2.5  Fe2O8 

83 

9  MO 

2(9  R208 

•  20  SiO2) 

9  MO  =  3  MgO  •  5  K2O  •  1  Na2O 

t 

St.  Etienne 

•12H2O 

18  R2O3  =  17  A12O3  •  1  Fe2O3 

THE   MICA   GROUP 


373 


or  the  general  formula 

m  MO  •  2  (6  R203  •  18  Si02) 


nH,0. 


Analyst 

SiOj 

AljOa 

Fe20, 

FeO 

CaO 

MgO 

K,0 

Na,0 

H,0 

Total 

Ficinus 
Galbraith 

Theory 
II 

Theory 
IV 

53.56 
54.60 

52.28 
50.45 

24.03 
23.60 

29.63 
30.13 

7 

8 

.93 
.60 

1.96Mn2O3 
1.60Mn2O3 

3.48 
3.53 

0.69 
0.80 

1.45 
1.09 

10.49 
11.20 

4.55 
4.81 

0.75 
0.95 

1.34 
1.20 

7.84 
7.58 

100.00 
101.60 

100.00 
98.54 

» 

Theory 
V 

51.59 
50.11 

29.23 
29.37 

2.58 
2.23 

0.34 

0.95 
1.03 

6.73 
6.71 

0.74 
0.60 

8.18 
8.03 

100.00 
98.42 

Kobell 

Theory 
XXXIII 

53 
52 

.71 
.52 

30.43 

30.88 

0.89 
0.80 

3.48 
3.82 

7.02 
6.38 

~ 

4.47 
4.60 

100.00 
99.00 

Miiller 

Theory 
C 

36.82 
36.08 

4 

4 

.32 
.99 

25.92 
25.98 

14.73 
14.28 

5.25 
5.43 

— 

8.02 
7.96 

3.69 
3.68 

1.22 
1.31 

100.00 
99.71 

Bromeis 

Theory 
XXII 

43 

43 

27 
02 

17 
16 

.37 

.85 

11 
11 

.22 
.63 

— 

18.83 
19.11 

8.07 
8.60 

1.24 
1.16 

z 

100.00 
100.36 

Konig 

Theory 

cxxxv 

33 
33 

06 

28 

14.84 

14.88 

6.12 
6.36 

0.55 
0.57 

21.74 
21.52 

— 



23.69 
23.90 

100.00 
100.51 

C.v.Hauer 

Theory 
XLV 

38 
38 

26 
13 

21 

21 

82 
60 

19.77 
19.92 

13.81 
13.76 

2.51  MnO 
2.61  MnO 

— 

3.83 
3.98 

100.00 
100.00 

Bromeis 

Theory 
LIV 

39.71 
39.75 

16.88 
15.99 

8 
8 

82 
29 

— 

1.02 

0.87 

24.26 
24.49 

8.64 
8.78 

= 

0.67 
0.75 

100.00 
98.92 

or  the  general  formula 
m  MO  •  2  (9  R203  •  12  Si02) 

•nH2 

0. 

Analyst 

SiO, 

A120, 

Fe,O,      FeO 

CaO 

MgO             KjO 

Na,O 

H,0 

Total 

Jewrechow 

Theory 
XV 

34.26 
34.02 

43.68 
43.33 

—     3.42 
—      3.02 

12.67 
13.11 

0.84  MnO      — 
1.05  MnO      — 

— 

5.13 
5.34 

100.00 
99.87 

Kdnig 

Theory 
I 

29.48 
28.96 

36.56 
37.49 

1.64    2.22 
1.26    2.46 

— 

17.20      2.88    ( 
17.35      2.46    ( 

3.34 
5.73 

3.68 
4.00 

100.00 
100.69 

M 

Theory 
II 

29.48 
29.50 

36.56 
37.56 

1.64    2.22 
1.40     2.42 

- 

17.20      2.88    < 
17.20       2.42    ( 

3.34 
5.24 

3.68 
3.32 

100.00 
100.02 

or  the  general  formula 

m  MO  •  2  (9  R203  •  20  Si02)  •  n  H20. 


Analyst 

SiOa 

A1203 

Fe208 

FeO 

CaO 

MgO 

K,0 

Na,O 

H,0 

Total 

Renard 

Theory 
III 

47.33 
47.02 

35.19 
34.82 

1.58 
2.57 

1.41 
0.68 

0.55 
0.20 

0.79 
0.52 

4.63 
4.60 

0.18 

8.52 
8.35 

100.00 
98.94 

Roepper 

Theory 
VIII 

46.66 
47.02 

33.71 
33.27 

3.11 

2.84 

z 

~ 

— 

10.05 
9.97 

~ 

6.47 
6.71 

100.00 
99.79 

Boricky 

Theory 
XXX 

48.91 

48.74 

37.42 
37.96 

z 

— 

2.85 
2.63 

2.44 
2.41 

2.87 
3.07 

— 

5.51 
5.45 

100.00 
100.26 

Haughton 

Theory 
LVIII 

44.96 
44.64 

30.57 
30.18 

5.99 
6.35 





0.75 
0.72 

12.33 
12.40 



5.40 
5.32 

100.00 
99.61 

Heddle 

Theory 
LI 

45.24 
45.10 

29.80 
29.90 

7.54 

7.87 

0.03  MnO 

1.06 
0.62 

1.51 

0.72 

7.09 

7.84 

2.34 
2.56 

5.43 
5.51 

100.00 
100.15 

» 

Theory 
LIV 

45.24 
45.43 

29.80 
29.65 

7.54 
8.33 

0.02  MnO 

1.06 
0.79 

1.51 
1.70 

7.09 
6.94 

2.34 

2.27 

5.43 
5.29 

100.00 
100.42 

Delesse 

Theory 
XLVII 

46.67 
46.23 

33.71 
33.03 

3.12 
3.48 

__ 

__ 

1.94 
2.10 

9.14 

8.87 

1.21 
1.45 

4.21 
4.12 

100.00 
99.28 

374 


THE   SCAPOLITE   GROUP 


Source 


84 
85 
86 


10  MO  •  2(9  R2O3  •  20  SiO2) 
•4H20 

14  MO  •  2(9  A12O3  •  20  SiO2) 
•  11  H2O 

14MO-2(9AI2O3-20SiO)2 
•11H2O 


10  MO =4  K2O  •  3.5  Na2O  •  2.5  MgO 
18  R2O3=17.5  A1203  •  0.5  Fe2O3 

14  MO  =  1 .5  FeO  •  2  BaO  •  0.5  CaO 
•  4  MgO  •  4.5  K2O  •  1.5  Na2O 

14  MO  =  1.5  FeO  -  2  BaO  •  0.5  CaO 
•4MgO-4.5K2O-1.5Na2O 


Muscovite 


Zillertal 
Pfitschtal 


New  Formulae  for  the 
The  following  analyses  of  the  minerals 


A.  Si  •  R  •  Si               =3  R203  •  10  SiO» 

B.  Si  -  R  •  Si               =3  R203  -  12  Si02, 

/Si 

C.  R^Si                     -  3  R203  -  15  Si02, 

Vi 

D.  R  •  Si  -  Si  •  R         =5  R203  •  12  Si02, 

E.  Si  •  R  •  Si  •  R  •  SAi  =  5  R203  •  18  Si02, 

A.  Scapolites  of  the  type 

Si  •  &  •  Si  =  3  R203  •  10  Si02 

Source 

Analyst 

l 

6  MO  •  2(3  R2O3  •  10  SiO2) 

6  MO  =  3  MgO  •  2.5  K2O  •  0.5  H2O 

Algerite 

Crossley 

•6H2O 

6  R2O3=5.75  A12O3  •  0.25  Fe2O3 

Franklin  N.J. 

2 

9  MO  •  2(3  A12O3  •  10  SiO2) 

9  MO  =  4.25  CaO  •  4.25  Na2O  •  0.5  H2O 

St.  Lawrence 

Rammels- 

•2H2O 

Co.,  N.S. 

berg 

3 

9MO-2(3Al2O3-10SiO2) 

9  MO  =  5.75  CaO  •  2.75  Na2O 

Arendal 

Wolff 

•0.5H20 

-  0.25  MgO  -  0.25  K2O 

4 

9MO-2(3Al2O3-10SiO2) 

9  MO  =  6  CaO  •  2.25  Na2O  •  0.25  K2O 

Arendal 

D  amour 

•4H2O 

•0.5H2O 

5 

HMO-2(3Al2O3-10SiO2) 

11  MO  =  7.75  CaO  •  1.5  Na2O 

Mais  j  6 

G.  v.  Rath 

•2.5H2O 

•  0.25  K2O-  1.5  MgO 

6 

12  MO  •  8(3  R2O3  •  10  SiO2) 
•  40  H2O  •  4  CaCO3 

12MO  =  10K2O-2MgO 
•  24  R203  =  23  A12O3  •  1  Fe2O3 

Algerite 
Franklin  N.J. 

Hunt 

7 

23  MO  •  8(3  A12O3  •  10  SiO2) 

23  MO  =  12  CaO  •  10  Na2O  •  1  K2O 

Gulsj6 

Hermann 

-  2  H2O  •  3  CaCO3 

8 

22  MO  •  8(3  A12O3  •  10  SiO2) 

22  MO  =  12  MgO  •  10  K2O 

Algerite 

Crossley 

•26H20-4CaC03) 

•  24  R203  =  23  A1203  -  1  Fe2O3 

Franklin  N.J. 

9 

36  MO  •  8(3  A12O3  •  10  SiO2) 

36  MO  =  22  CaO  •  9  Na2O  •  2  K2O 

Mais  j  5 

G.  v.  Rath 

•  12H2O-lCaCO3 

•  3  MgO 

10 

30  MO  •  8(3  A12O3  •  10  SiO2) 

30  MO  =  20  CaO  •  10  Na2O 

Kupfermine 

Lacroix 

•2H2O-1  CaS04 

THE   ORTHOCHLORITE   GROUP 


375 


Analyst 

SiOj 

AlaO, 

Fe20, 

FeO 

CaO 

MgO 

KaO 

Na,0 

H,0 

Total 

Schafhautl 

Theory 
XXXVI 

47.72 
47.05 

35.49 
34.90 

1.59 
1.50 

___ 

— 

1.98 
1.95 

7.47 
7.96 

4.32 
4.07 

1.43 
1.45 

100.00 

98.88 

Rammels- 
berg 

Theory 
XL 

43.39 
43.09 

33.19 
32.79 

5.51  BaO 
5.91  BaO 

1.95 
1.85 

0.56 
0.23 

2.88 
2.90 

7.28 
7.61 

1.68 
1.42 

3.56 
4.26 

100.00 
100.35 

Rammels- 
berg 

Theory 
XLI 

43.39 
42.90 

33.19 
32.40 

5.51  BaO 
5.82  BaO 

1.95 
2.40 

0.56 
0.80 

2.88 
2.87 

7.28 
7,47 

1.68 
1.73 

3.56 
3.02 

100.00 
99.41 

Scapolito  Group 

of  this  group  conform  to  the  following  formulae  : 

F.  Si  •  R  .  Si  •  Si  •  R  •  Si         =5  R203  •  22  Si02, 

G.  R  •  Si  •  Si  •  R 

H.  Si  •  R  •  Si  •  R  •  Si 

J.  Si  •  R  •  Si  •  R  •  Si 

K.  Si  •  R  •  SAi  •  Si  •  R  •  Si 

L.  Si  •  R  •  Si  •  R  •  Si  •  R  •  Si  =  9  R203  •  20  Si02. 

or  the  general  formulae 

(a)  m  MO  •  2  (3  R203  •  10  Si02)  •  n  H20, 

(b)  m  MO  •  8  (3  R203  •  10  Si02)  •  n  H20  •  p  CaC03  (or  p  CaS04). 


=  6  R203  •  12  Si02, 
=  6  R203  •  16  Si02, 
=  6  R203  •  18  Si02, 
=  6  R203  •  22  Si02, 


SiOa 

Al,0, 

Fe.0, 

FeO  |       MgO 

CaO 

K8O 

NazO 

HaO 

NaCl 

CaCO, 

CO, 

a 

Total 

Theory 
LXXXIa 

52.21 
52.00 

25.52 
25.42 

1.74 
1.54 

- 

5.22 
5.39 

— 

10.22 
10.38 

— 

5.09 
5.27 

— 



— 



100.00 
100.00 

Theory 
XCII 

50.88 
50.73 

25.95 
25.40 

- 

— 

~ 

10.09 
10.24 



11.17 
11.09 

1.91 
1.96 

___ 

— 



0.09 

100.00 
99.60 

Theory 
XXX 

51.14 
50.91 

26.07 
25.81 

0.75 

— 

0.43 
0.58 

13.75 
13.34 

1.00 
0.85 

7.26 
7.09 

0.38 
0.41 

__ 

— 



— 

100.00 

99.74 

Theory 
XXXVI 

50.17 
50.30 

25.58 
25.08 

— 

— 

— 

14.05 
14.08 

0.98 
1.01 

5.83 

5.98 

3.39 
3.25 

— 

. 





100.00 
99.70 

Theory 
XLII 

48.63 
47.24 

24.81 
24.69 

Trace 

2.43 
2.18 

17.59 
16.84 

0.95 
0.85 

3.77 
3.55 

1.82 
1.72 





___ 

— 

100.00 
98.07 

Theory 
LXXX 

50.81 
49.82 

24.84 
24.91 

1.69 
1.85 

— 

0.85 
1.15 

2.37 

2.20 

9.95 
10.21 

Trace 

7.57 

— 



1.86 
1.74 

— 

100.00 
99.45 

Theory 
XLV 

53.52 
52.94 

27.29 
27.64 

— 

0.30 

0.25  MnO 

9.36 
9.10 

1.05 
0.54 

6.91 
6.89 

0.40 
0.66 



— 

1.47 
1.50 

— 

100.00 
99.72 

Theory 
LXXXI 

50.03 
49-96 

24.45 
24.41 

1.68 
1.48 

— 

5.00 
5.18 

___ 

9.80 
9.97 

_ 

4.87 
5.06 



4.17 
4.21 





100.00 
100.27 

Theory 
XLI 

49.68 
49.36 

25.33 
25.33 

— 

__ 

1.24 
1.05 

12.75 
12.47 

1.95 
1.51 

5.77 

5.81 

2.24 
2.42 

— 

1.04 
1.35 





100.00 
99.35 

Theory 
CXV 

52.41 
52.62 

26.72 

26.42 

Trace 

z 

~ 

12.84 
13.11 

0.45 

6.77 
6.62 

0.39 
0.43 

0.87  SO3 
0.79  SO8 

__ 

__ 

0.10 

100.00 
100.54 

376 


THE   SCAPOLITE   GROUP 


B.  Scapolites  of  the  type 
-R-SAi  =  3R203-12Si02 


Source 

Analyst 

11 

9  MO 

•  2(3  A12O3 

•  12  SiO2) 

9  MO  =4.25  CaO  •  4.25  Na2O  •  0.5  K2O 

Mizzonite 

Rath 

12 
13 

9  MO 
15  MO 

•  2(3  A12O3 
•  1H2O 

•  4(3  A1O3  • 
•  3NaCl 

•12SiO2) 
12  SiO2) 

9  MO=4.25  CaO  •  1.75  K2O  •  1.5  Na2O 
•  1  MgO  •  0.5  H2O 

15  MO  =  9  CaO  •  5.5  Na2O  •  0.5  K2O 

Dipyre  from 
Pouzac 

St.Lawrence 
Co.,  N.S. 

H.  Schulz 
Lemberg 

C.  Scapolites  of  the  type 

/s 

R— Si  =  3  R203  •  15  Si02 


14 
15 

Source 

Analyst 

8  MO 
10  MO 

•  2(3  Al20a 

•  2(3  A1202 
•4H2O 

•  15  SiO2) 
•  15  SiO2) 

8  MO  =4.5Na2O  -  2.5  CaO  •  0.5  MgO 
•  0.5  K2O 

10  MO  =5.5  MgO  •  3  K2O  •  0.75  FeO 
•  0.25  Na2O  •  0.5  CaO 

Marialite, 
Pianura 

Couseranite, 
Pouzac 

G.  v.  Rath 
Pisani 

D.  Scapolites  of  the  type 
R"-  Si  -  Si  -  RT=  5  R203  •  12  Si02 


Source 

Analyst 

16 

10MO-2(5A1203- 

12  SiO2) 

10  MO  =  10  CaO 

Stansvik 

Lagus 
Olckonen 

17 

10MO-2(5A1203- 
•2H20 

12  Si02) 

10MO=9CaO-lNa2O 

Clay  Co.,  N.C. 

Berkley 

18 

11MO-2(5A12O3- 
•2H20 

12  SiO2) 

HMO  =  10CaO-0.5K2O 
•  0.5  Na2O 

Pargas 

Wolff 

19 

11MO-2(5A1203- 
•17H20 

12  SiO2) 

HMO  =  4MgO-3CaO 
•  3  K2O  •  1  Na2O 

Wilsonite 
Bathurst,  Canada 

Selkmann 

20 

12MO-2(5A12O3- 

12  SiO2) 

12  MO  =  12  CaO 

Stansvik 

Lagus 
Olckonen 

21 

14MO-2(5A12O3- 

12  SiO2) 

14MO  =  12CaO-1.5Na2O 
•  0.5  K2O 

Ersbyite,  Pargas 

N.  Norden- 
skiold 

22 

15MO-2(5A12O3- 

12  SiO2) 

15MO  =  13CaO-2Na2O 

Baikalsee 

Hermann 

23 

15MO-2(5A12O3- 

12  SiO2) 

15  MO  =  13  CaO  -1  MgO 
•  0.5  K2O  •  0.5  Na2O 

Mejonite  from 
Vesuvius 

G.  v.  Rath 

24 

18MO-2(5A12O3- 
•14H20 

12SiO2) 

18  MO  =  15.5  CaO  •  2.5  MgO 
•10R2O3  =  8.5Al2O3-1.5Fe2O3 

Atheriastite, 
Arendal 

Berlin 

THE  SCAPOLITE   GROUP 


377 


or  the  general  formulae 

(a)  m  MO  •  2  (3  R203  •  12  SiO2)  •  n  H20, 

(b)  m  MO  •  4  (3  R203  •  12  Si02)  •  n  NaCl. 


SiO, 

Al,0, 

Fe20s 

FeO 

MgO 

CaO 

K,0 

Na,0 

H,0 

NaCl 

CaCO, 

CO, 

ci 

Total 

Theory 
XVI 

55.38 
54.70 

23.52 

23.80 

— 

z 

0.22 

9.15 

8.77 

1.82 
2.14 

10.13 
9.83 

0.13 

~ 

~ 

- 

— 

100.00 
99.59 

Theory 
XXIII 

55.08 
53.97 

23.41 
23.68 

z 

-^ 

1.53 
1.40 

9.10 
8.76 

6.29 
6.43 

3.56 
3.55 

1.03 
0.98 

~ 

~ 

- 

- 

100.00 

98.77 

Theory 
XCIV 

55.69 
55.04 

23.67 
23.62 

z 

- 

~ 

9.75 
9.38 

0.91 
0.73 

6.59 
6.29 

0.28 

3.39 
3.69 

~ 

- 

~ 

100.00 
99.03 

or  the  general  formula 

m  MO  •  2  (3  R203  •  15  Si02)  •  n  H20. 


SiO, 

Al,0, 

Fe,0, 

FeO 

MgO 

CaO 

K,0 

Na,O 

H,0 

NaCl 

CaCO, 

CO, 

Cl 

Total 

Theory 
XVIII 

62.11 

62.72 

21.12 
21.82 

z 

z 

0.69 
0.31 

4.83 
4.62 

1.62 
1.15 

9.63 
9.37 

— 

Z 

— 

z 

— 

100.00 
100.00 

Theory 
XXV 

58.37 
58,33 

19.85 
20.20 

- 

1.75 
1.90 

7.14 

7.20 

0.90 
0.99 

9.15 

8.82 

0.50 
0.76 

2.34 
2.35 

— 

~ 

- 

- 

100.00 
100.55 

or  the  general  formula 

m  MO  •  2  (5  R203  •  12  Si02)  •  n  H20. 


SiO, 

Al,0, 

Fe20, 

FeO 

MgO 

CaO 

K,0 

Na20 

HaO 

NaCl 

CaC03 

CO, 

Cl 

Total 

Theory 

LXVHI 

47.68 
47.60 

33.77 
33.50 

- 

- 

z 

18.55 
17.20 

~ 

— 

__ 



___ 



— 

100.00 
98.30 

Theory 
LXXVIII 

47.03 
47.54 

33.31 
34.03 

- 

— 

- 

16.46 
17.23 

— 

2.02 
1.82 

1.18 
1.02 



— 

— 



100.00 
101.64 

Theory 
LIX 

45.95 
45.10 

32.55 
32.76 

- 

— 

— 

17.87 
17.84 

1.50 
0.68 

0.99 
0.76 

1.14 
1.04 

— 





— 

100.00 
98.18 

Theory 
CXIII 

41.88 
41.26 

29.66 
30.31 

- 

— 

4.66 
4.20 

4.89 
5.34 

8.20 
7.43 

1.80 
1.97 

8.91 
8.83 





— 

— 

100.00 
99.34 

Theory 
LXIX 

45.98 
45.60 

32.56 
32.60 

— 

- 

— 

21.46 
23.40 

— 

z 

z 

— 







100.00 
101.60 

Theory 
LVII 

44.02 
44.26 

31.17 
30.37 

— 

- 

0.15 

20.54 
20.17 

1.43 
1.15 

2.84 
2.75 

— 









100.00 
98.85 

Theory 
LXXVa 

43.48 
43.35 

30.80 
30.52 

0.95 

— 

~ 

21.98 
21.59 

z 

3.74 
3.74 

__ 



— 





100.00 
100.15 

Theory 
XIII 

43.56 
42.55 

30.85 
30.89 

0.41 

— 

1.21 
0.83 

22.02 
21.41 

1.42 
0.93 

0.94 
1.25 

__ 









100.00 
98.46 

Theory 
XXXVIII 

38.23 
38.00 

23.02 
24.10 

6.37 
5-60 

- 

2.65 
2.80 

23.04 
22.64 

— 

— 

6.69 
6.95 

___ 

_ 



— 

100.00 
100.09 

378 


THE   SCAPOLITE   GROUP 


E.  Scapolites  of  the  type 
Si  •  R  •  Si  •  R  •  Si  =  5  R203  •  18  Si02 


Source               Analyst 

25 

HMO 

•2(5R2O3- 

18SiO2) 

H  MO  =  9  CaO  •  4.5  Na2O  •  0.5  K2O 

Mais  j  6            SipOcz 

26 

HMO 

•2(5R2O3- 

18  SiO2) 

14  MO  =  6  CaO  •  3  K2O  •  3  MgO-1  Na2O 

Tiree          F.  Heddle 

•HH20 

.  1  FeO  ;  10  R2O3=9  A12O3  •  1  Fe2O3 

27 

32  MO 

•2(5A12O3 

•18SiO2) 

32MO  =  31CaO-lMgO 

Storgard     Norden- 

•10H20 

skiold 

28 

8  MO 

•  2(5  R2O3  • 

18SiO2) 

8  M0=3.5  K20  •  2.5  CaO  •  2  MgO 

Bolton,          G.  v.  Rath 

•10H2O-3CaCO3) 

10  R2O3=9.5  A12O3  •  0.5  Fe2O3 

Mass. 

F.  Scapolites  of  the  type 

Si  •  R  •  SAi  •  Si  •  R  •  Si  =  5  R203  •  22  Si02 

Source 

Analyst 

29 

12  MO 

•2(5R2O8- 

22  SiO2) 

12  MO  =  6.5  Na2O  •  5  CaO  •  0.5  MgO 

Coquimbo 

Jannetaz 

•10H2O 

10R203=9Al2O3-lFe203 

30 

15  MO 

•2(5Al2Oa 

•22SiO2) 

15  MO  =  3  MgO  •  6  CaO  •  6  Na2O 

Bamle 

Vogt 

G.  Scapolites  of  the  type 

R  •  Si  •  Si  •  R  =  6  R203  •  12  Si02 

Source 

Analyst 

31 

11  MO 

2(6A12O8- 

12SiO2) 

HMO  =  llCaO 

Helsingfors 

Wilk 

32 

11  MO 

2(6A12O8- 

12SiO2) 

HMO  =  llCaO 

Pargas 

Norden- 

•2H20 

skiold 

H.  Scapolites  of  the  type 

Si  •  R  •  Si  •  R  •  Si  =  6  R203  •  16  Si02 

Source 

Analyst 

33 

9  MO 

•2(6R20S 

16SiO2) 

9  MO  =  6  CaO  •  3  Na2O  •  12  R2O3 

Petteby 

Hartwall 

•2H20 

=  11.5Al2O3-0.5Fe2O3 

34 

10  MO 

•2(6A1203 

•16SiO2) 

10  MO  =  4.5  MgO  •  4  K2O  •  1  CaO 

Bathurst, 

Hunt 

•12H2O 

•0.5Na20 

Canada 

35 

13  MO 

•2(6R203- 

16  SiO2) 

13  MO  =  10.5  CaO  •  1.5  Na2O-0.5  K2O 

Diana,Lewis 

Hermann 

•0.5H2O;  12R2O3=--11.5Al2O3-0.5Fe2O3 

Co.,  N.S. 

36 

13  MO 

•2(6A1203 

•16SiO2) 

13MO  =  llCaO-2Na2O 

Ersby 

Hartwall 

•1H20 

Herdberg 

37 

HMO 

•  2(6  A12O3 

•16SiO2) 

14  MO  =  5  CaO  •  4  MgO  •  4  K2O 

Bathurst, 

Hunt 

•  21  H20 

•  1  Na20 

Canada 

38 

17  MO 

•2(6A1203 

•  16  SiO2 

17  MO  =  14.5  CaO  •  2  Na2O  •  0.5  K2O 

Laacher  See 

Rath 

•1H20 

39 

18  MO 

•  2(6  R2O3 

16  SiO2) 

18  MO  =  15.5  CaO  •  1.5  Na2O  •  1  MgO 

Bolton, 

G.  v.  Rath 

•3H2O 

1  2  R2O3  =  1  1  A12O3  •  1  Fe2O3 

Mass. 

THE   SCAPOLITE   GROUP 


379 


or  the  general  formulae 

(a)  m  MO  •  2  (5  R203  •  18  Si02)  •  n  H20, 

(b)  m  MO  •  2  (5  R203  •  18  SiO2)  •  n  H20.  p  CaC03. 


Si02 

Al,0, 

Fe,0, 

FeO 

MgO 

CaO 

K80 

Na,O 

H,0 

Nad 

CaCO, 

CO, 

Cl 

Total 

Theory 
XLIII 

53.86 
52.48 

25.44 
25.56 

- 

0.39 

___ 

12.57 
12.44 

1.17 
0.79 

6.96 
6.52 

0.61 

0.58  SO3 



0.14 

0.27 

100.00 
99.78 

Theory 
XXIX 

49.52 
48.92 

21.05 
22.10 

3.67 
3.16 

1.65 
1.51 

2.75 

2.77 

7.70 
7.75 

6.47 
6.06 

1.42 
1.28 

5.77 
5.69 

0.54  MnO 





— 

100.00 
99.78 

Theory 
LV 

42.06 
41.25 

19.86 
20.36 

— 

z 

0.78 
0.54 

33.80 
33.58 

z 

~ 

3.50 
3.32 

— 



— 

— 

100.00 
99.05 

Theory 
CVI 

50.97 
49.99 

22.87 
23.01 

1.89 
1.64 

- 

1.89 
1.73 

3.30 
3.35 

7.76 
7.09 

0.35 

4.25 
4.23 

— 

7.07 
7.80 

___ 

— 

100.00 
99.19 

or  the  general  formula 

m  MO  •  2  (5  R203  •  22  Si02)  •  n  H2O. 


SiO2 

Al,0, 

Fe,0, 

FeO 

MgO 

CaO 

K,0 

Na,O 

H,0 

NaCl 

CaCO, 

CO, 

Cl 

Total 

Theory 
LXXVII 

57.38 
57.40 

19.95 
19.60 

3.48 
3.40 



0.43 
0.40 

6.09 
6.20 

Trace 

8.76 
8.80 

3.91 
3.41 

__ 

___ 

— 



100.00 
99.21 

Theory 
XXXIX 

58.82 
59.66 

22.73 
22.65 

— 

— 

2.67 
2.60 

7.49 
7.32 

- 

8.29 
8.13 

~ 

— 

z 

— 

- 

100.00 
100.36 

or  the  general  formula 

m  MO  •  2  (6  R203  •  12  Si02) 


nH20. 


SiO, 

Al,0, 

Fe,0, 

FeO 

MgO 

CaO   |  KaO 

Na20 

H20 

NaCl 

CaCO, 

CO, 

Cl 

Total 

Theory 
LXX 

43.90 
43.63 

37.32 
36.93 

- 

~ 

~ 

18.78 
18.37 

— 

- 

~ 

- 

— 

- 

- 

100.00 
98.93 

Theory 
LIII 

43.43 
43.83 

36.91 
35.43 

- 

- 

~ 

18.57 
18.96 

z 

- 

1.09 
1.03 

— 

— 

— 

- 

100.00 
99.25 

or  the  general  formula 

m  MO  •  2  (6  R203  •  16  SiO2)  •  n  H20. 


SiO, 

Al,0, 

Fe2O» 

FeO 

MgO 

CaO 

KaO 

Na2o|  HaO 

NaCl 

CaCO, 

CO, 

Cl 

Total 

Theory 
LXVII 

51.46 
51.34 

31.44 
32.27 

2.15 
1.91 

— 

— 

9.01 
9.33 

- 

4.98 
5.12 

0.96 
1.00 

— 

— 

— 

— 

100.00 
100.97 

Theory 
CXII 

47.97 
47.60 

30.58 
31.20 

~ 

z 

4.50 
4.19 

1.40 
0.95 

9.39 
9.30 

0.77 

0.88 

5.39 
5.43 

z 

z 

z 

z 

100.00 
99.55 

Theory 
LXXXVI 

49.10 
47.94 

30.00 
30.02 

2.05 
2.60 

0.26  MnO 

z 

15.04 
14.41 

1.20 
0.73 

2.38 
2.20 

0.22 
0.31 



___ 

z 

z 

100.00 

98.47 

Theory 
LXV 

49.20 

48.87 

31.37 
31.05 



__ 

— 

15.79 
15.94 



3.18 
3.25 

0.46 
0.61 

__ 

— 

z 

z 

100.00 
99.62 

Theory 
CXI 

43.64 
43.55 

27.82 
27.94 

0.20 

— 

3.63 
3.81 

6.36 
6.50 

8.55 
8.37 

1.41 
1.45 

8.59 
8.61 

— 

— 

___ 

z 

100.00 
100.43 

Theory 

46.32 
45.13 

29.53 
29.83 

— 

- 

0.13 

19.59 
18.98 

1.14 
1.40 

2.99 
2.73 

0.43 
0.41 

— 

— 

— 

— 

100.00 
98.61 

Theory 
CV 

45.09 
44.40 

26.35 
25.52 

3.76 
3.79 

— 

0.94 
1.01 

20.39 
20.18 

0.51 

2.18 
2.09 

1.29 
1.24 

- 

— 

— 

— 

100.00 

98.74 

380 


THE   SCAPOLITE   GROUP 


J.    Scapolites  of  the  type 
R  •  Si  •  R  •  Si  =  6  R203  •  18  Si02 


Source 

Analyst 

40 

2MO-2(6A12O3-18S102) 

2  MO  =  1.5  Na2O  •  0.5  H2O 

St.  Lawrence 

Rammels- 

•6H20 

Co.,  N.S. 

berg 

41 

3  MO  •  2(6  A12O3  •  18  SiO2) 

3  MO  =  1  CaO  •  1  Na2O  •  0.5  MgO 

Bolton, 

Hermann 

•2H2O 

•  0.5  K2O 

Mass. 

42 

14  MO  •  2(6  A12O3  •  18  SiO2) 
•1H20 

14  MO  =  10  CaO  •  2.5  Na2O  •  0.5  FeO 
•  0.5  K2O  •  0.5  MgO 

Boxborough 

Becke 

43 

14MO-2(6Al2O3-18SiO2) 

14  MO  -8  CaO  •  3.5  MgO  •  2  Na2O 

Glaukolite 

Berge- 

•4H20 

•  0.5  K2O 

Baikalsee 

mann 

44 

14MO-2(6Al203-18Si02) 

14  MO  =  8.5  CaO  •  2.5  MgO  •  2  Na2O 

tt 

Giwar- 

•4H20 

•  0.5  MnO  •  0.5  K2O 

towsky 

45 

15MO-2(6Al203-18SiO2) 

15MO  =  llCaO-4Na20 

Obernzell 

Fuchs 

•2H20 

bei  Passau 

46 

17  MO  •  2(6  A12O3  •  18  SiO2) 

17  MO  =  12  CaO  •  3  Na2O  •  1.5  MgO 

Bolton, 

Wolff 

•2H2O 

•  0.5  K2O 

Mass. 

47 

18MO-2(6R203-18Si02) 

18MO  =  13.5CaO-3.5Na2O-  1  MgO 

Hirvensalo 

M 

•2H20 

12  R203=11.5Al203-0.5Fe2O3 

48 

18MO-2(6Al203-18SiO2) 

18  MO  =  14  CaO  •  3.5  Na2O  •  0.5  MgO 

Drothem 

Berg 

•4H20 

49 

18  MO  •  2(6  A12O3  •  18  SiO2) 

18  MO  =  15.5  CaO  •  2.5  Na2O 

Bolton, 

Thomson 

•13H20 

Mass. 

50 

19  MO  •  2(6  A12O3  •  18  SiO2) 

19  MO  =  14.5  CaO  •  2.5  Na2O  • 

Bucks 

Leeds 

•4H20 

-  1.5  MgO  •  0.5  K20 

Co.,  Pa. 

51 

19  MO  •  2(6  A12O3  •  18  SiO2) 

19  M0  =  ll  CaO  •  4  MgO  •  2  Na2O 

Perth, 

Hunt 

•7H20 

•2K20 

Canada 

52 

20MO-2(6R2O3-18SiO2) 

20MO  =  14CaO-6Na20 

Bolton, 

Wurtz 

12  R2O3=  11.5  A12O3  •  0.5  Fe2O3 

Mass. 

53 

20MO-2(6R2O3-18SiO2) 

20  MO  =  14  CaO  •  5.5  Na2O  •  0.5  K2O 

Arendal 

G.  v.  Rath 

•1H2O 

12  R2O3  =  11.5  A12O3  •  0.5  Fe2O3 

54 

22MO-2(6R2O3-18SiO2) 

22  MO  =  18  CaO  •  2  Na2O  •  1.5  MgO 

Bolton, 

M 

•2H20 

•0.5  K2O  ;  12  R2O3=11A12O3-  1  Fe2O3 

Mass. 

55 

HMO-2(6R203-18Si02) 

1  1  MO  =  10  CaO  •  0.5  MgO  •  0.5  K2O 

Hesselkulla 

Hermann 

•  3  Na2C03 

12  R,O,  =  11.25  A12O3  •  0.75  Fe2O3 

56 

12MO-2(6Al203-18SiO2) 

12  MO  =  12  CaO 

Obernzell 

Fuchs 

-6  Had 

bei  Passau 

57 

15  MO  •  2(6  A12O3  •  18  SiO2) 

15  MO  =  12  CaO  •  2.5  Na2O  -  0.5  K2O 

Ersby 

Lemberg 

•2H2O-lNaCl 

THE   SCAPOLITE   GROUP 


381 


or  the  general  formulse 

(a)  m  MO  •  2  (6  R203  •  18  Si02)  •  n  H20, 

(b)  m  MO  •  2  (6  R203  •  18  Si02)  •  p  Na2C03  (or  p 


Nad). 


Si02 

A1Z08 

Fe20, 

FeO 

MgO 

CaO 

K20 

Na20 

H20 

NaCl 

CaC08 

CO, 

Cl 

Total 

Theory 
XCIII 

60.10 
59.29 

34.05 

34.78 

z 

— 

0.07 

0.11 

— 

2.59 
2.31 

3.26 
3.31 

— 

Z 

- 

0.20 

100.00 
100.07 

Theory 

cm 

52.56 
51.68 

29.79 
29.30 

z 

— 

0.49 
0.78 

13.63 
13.51 

1.14 
0.94 

1.61 

1.46 

0.88 
0.82 

0.15MnO 

z 

- 

z 

100.00 
99.80 

Theory 
CVIII 

51.19 

50.53 

29.00 
29.31 

— 

0.85 
0.49 

0.47 
0.46 

13.27 
13.37 

1.11 
1.23 

3.68 
3.91 

0.43 
0.54 

~ 

— 

- 

0.21 

100.00 
100.05 

Theory 
LXXII 

51.25 
50.58 

29.03 
27.60 

0.86Mn2O3 

0.10 

3.32 
3.72 

10.63 
10.27 

1.11 
1.27 

2.94 
2.97 

1.72 
1.73 









100.00 
99.11 

Theory 
LXXIII 

50.96 
50.49 

28.88 
28.12 

0.40  FeO 

0.84MnO 
0.60  MnO 

2.36 
2.68 

11.23 
11.31 

1.10 
1.00 

2.93 
3.10 

1.70 
1.79 





— 



100.00 
99.49 

Theory 
II 

50.42 
49.30 

28.57 
27.90 

z 

z 

z 

14.38 
14.42 

~ 

5.79 
5.46 

0.84 
0.90 

— 

- 

z 

z 

100.00 
97.98 

Theory 
C 

49.26 
48.79 

27.92 
28.16 

0.32 

~ 

1.37 
1.29 

15.33 
15.02 

1.07 
0.54 

4.24 
4.52 

0.81 
0.74 

- 

z 

z 

— 

100.00 
99.38 

Theory 
LII 

48.41 
48.15 

26.29 
25.38 

1.79 
1.48 

z 

0.90 
0.84 

16.94 
16.63 

0.12 

4.86 
4.91 

0.81 
0.85 

- 

— 

z 

z 

100.00 
98.36 

Theory 
XLVII 

48.25 
46.35 

27.34 
26.34 

0.32 

- 

0.45 
0.54 

17.51 
17.00 

0.32 

4.85 
4.71 

1.60 
1.60 

0.99  ResU 

- 

— 

— 

100.00 
98.17 

Theory 
XCIX 

46.54 
46.30 

26.37 

26.48 

— 

~ 

- 

18.71 
18.64 

— 

3.34 

3.64 

5.04 
5.04 

~m 

z 

— 

z 

100.00 
100.08 

Theory 
LXXXV 

47.68 

47.47 

27.02 
27.51 

— 

— 

1.32 

1.20 

17.93 
17.59 

1.04 
1.40 

3.42 
3.05 

1.59 

1.48 

— 

z 

— 

z 

100.00 
99.70 

Theory 
CX 

46.97 
46.30 

26.62 
26.20 

— 

— 

3.48 
3.63 

13.39 

12.88 

4.08 
4.30 

2.70 
2.88 

2.76 
2.80 

— 

z 

— 

— 

100.00 
98.99 

Theory 
CI 

47.29 
47.67 

25.66 
25.75 

i.75 
2.26 

- 

z 

17.16 
17.31 

— 

8.14 
7.76 

z 

z 

— 

- 

- 

100.00 
100.75 

Theory 
XXXII 

46.93 

46.82 

25.48 
26.12 

1.74 
1.39 

— 

0.26 

17.03 
17.23 

1.02 
0.97 

7.41 

6.88 

0.39 
0.33 

z 

z 

- 

z 

100.00 
100.00 

Theory 
CIV 

45.79 
45.57 

23.79 
23.65 

3.39 
3.38 

— 

1.27 
1.23 

21.37 

20.81 

1.00 
0.63 

2.63 
2.46 

0.76 

0.78 

- 

- 

- 

z 

100.00 
98.51 

Theory 
L 

49.40 
49.49 

26.25 
26.06 

2.74 

2.65 

0.25  MnO 

0.46 
0.36 

12.81 
12.89 

1.07 

0.80 

4.25 
4.50 

z 

- 

- 

3.02 
3.00 

— 

100.00 
100.00 

Theory 
III 

49.01 

49.42 

27.78 
27.50 

z 

z 

15.25 
15.25 

— 

— 

— 

7.96 

7.83 

- 



— 

100.00 
100.00 

Theory 
LXIII 

49.62 
49.30 

28.12 
26.99 

— 

— 

15.44 
15.59 

1.08 
0.69 

3.56 

3.48 

0.83 
0.66 

1.35 
1.35 

z 

— 

- 

100.00 
98.06 

382 


THE  SCAPOLITE   GROUP 


K.  Scapolites  of  the  type 
Si  •  R  •  Si  •  Si  •  R  •  Si  =  6  R203  •  22  Si02 


Source 

Analyst 

58 

14MO-2(6R203-22SiO2) 

14  MO  =  7.5  CaO  •  4  K2O  •  2.5  MgO 

Bolton,  Mass. 

G.  v.  Rath 

•  12  H20 

12  R2O3=11.5  A12O3  -  0.5  Fe2O3 

59 

18MO-2(6Al2O3-22SiOa) 

18  M0  =  9  CaO  •  7  Na2O  -  1  K2O 

St.  Lawrence 

•4HaO 

•IMgO 

Co.,  N.S. 

60 

20  MO  •  2  (6  A12O3  •  22  SiO2) 

20  MO  =  10  Na2O  •  9  CaO  •  1  K2O 

Monzoni 

Kiepen- 

heuer 

61 

20  MO  •  2  (6  A12O3  •  22  SiO2) 

20  MO  =  7.5  Na2O  •  7  CaO  •  3.5  MgO 

Dipyre,Breno 

Salomon 

•4H2O 

•  1  K20  •  1  H2O 

62 

14  MO  •  2  (6  A12O3  •  22  SiO2) 
•2NaCl 

14  MO  =  10  CaO  •  3  Na2O  •  1  K2O 

Steinhag 

Wittstein 

63 

14MO-2(6AlaO3-22SiO2) 

14  MO  =  8.5  CaO  -  0.5  K2O  •  5  Na2O 

French  Creek, 

Genth 

•4H2O-3CaCO3 

Pa. 

64 

15MO-2(6Al203-22SiO2) 
•2H2O-2NaCl 

15  MO  =  8.5  CaO  •  6.5  Na2O 

Pargas 

Rammels- 
berg 

65 

15MO-2(6Ala03-22SiO2) 
•2H2O-2NaCl 

15  MO  =  9  CaO  •  4  Na2O  •  2  K2O 

" 

»» 

66 

15  MO.-  2  (6  A12O3  •  22  SiO2) 

15  MO  =  9.5  CaO  •  4.5  Na2O  •  1  K2O 

St.  Lawrence 

n 

•  4  NaCl 

Co.,  N.Y. 

L.  Scapolites  of  the  type 
-R-Si  =  9  R203  •  20  Si02 


Source 

Analyst 

67 

68 

16MO-2(9Al203-20Si02) 
•  18  H20 

24MO-2(9AlaO3-20SiO2) 

16  MO  =9  CaO  -  4  Na2O  •  1.5  MgO 
•1.5K2O 

24  MO  =  20.5  CaO  -  2.5  Na2O  •  1  FeO 

Saleix,  Ariege 
Vesuvius 

Grandeau 
Gmelin 

69 

70 

26  MO  •  2  (9  R2O3  •  20  SiO2) 
•6H2O 

22  MO  •  2  (9  A12O3  •  20  SiO2) 
•  4  CaCO3 

26  MO  =  21  CaO-  5  K2O 
18  R203=  15  A12O3  •  3  Fe2O3 

22  MO  =  19.5  CaO  -  2.5  NaaO 

Bolton,  Mass. 
Vesuvius 

Muir 
Gmelin 

THE   SCAPOLITE   GROUP 


383 


or  the  general  formulae 

(a)  m  MO  •  2  (6  R203  •  22  Si02)  •  n  H20, 

(b)  m  MO  •  2  (6  R2O3  •  22  Si02)  •  n  H20  •  p 


NaCl  (or  p  •  CaC03). 


SiOj 

AI,0, 

Fe20, 

FeO 

MgO 

CaO 

K,0 

Na20 

HaO 

NaCl 

CaCOa 

CO,  |    Cl    |     Total 

Theory 
CVIa 

52.75 
52.20 

23.42 
24.03 

1.60 
1.71 

z 

2.00 
1.80 

8.39 
8.06 

7.51 

7.40 

0.37 

4.33 
4.43 

— 

z 

z 

— 

100.00 
100.00 

Theory 
LXXXIX 

52.72 
52.25 

24.44 
23.97 

Trace 

~ 

0.80 
0.78 

10.06 
9.86 

1.88 
1.73 

8.67 
8.70 

1.43 
1.20 

— 

z 

— 

— 

100.00 
98.49 

Theory 
VII 

51.95 
52.19 

24.08 
23.54 

~ 

~ 

~ 

9.92 
9.61 

1.85 
2.11 

12.20 
12.65 

z 

z 

- 

z 

— 

100.00 
100.10 

Theory 
VIII 

52.71 
52.74 

24.44 
23.98 

0.40 

~ 

2.79 

2.77 

7.83 
7.43 

1.88 
1.86 

9.28 
9.00 

1.07 
1.18 

z 

- 

— 

— 

100.00 
99.36 

Theory 
VI 

54.76 
54.87 

25.39 
25.32 

z 

~ 

~ 

11.62 
11.63 

1.95 
1.50 

3.86 
3.86 

z 

2.42 
2.15 

- 

— 

— 

100.00 
99.33 

Theory 
LXXXIV 

52.08 
52.30 

24.15 
23.68 

0.58 

— 

0.05 

12.70 
12.36 

0.93 
0.77 

6.11 
6.29 

1.42 
1.50 

— 

- 

2.61 
2.63 

— 

100.00 
100.16 

Theory 
LXI 

54.04 
53.32 

24.91 
24.67 

— 

~ 

~ 

9.69 
9.84 

— 

9.46 
9.12 

0.73 
0.73 

- 

- 

— 

1.48 
1.73 

100.31* 
99.41 

Theory 
LXII 

53.43 
53.32 

24.60 

24.08 

- 

~ 

— 

10.13 
9.60 

3.78 
3.93 

6.23 
6.31 

0.72 
0.71 

— 

— 

— 

1.43 
1.71 

100.32* 
99.66 

Theory 
XCI 

52.93 
52.90 

24.38 
24.95 

- 

— 

- 

10.59 
10.54 

1.87 
1.53 

8.03 
8.10 

— 

— 

—  • 

— 

2.83 
2.33 

101.63* 
100.35 

or  the  general  formulse 

(a)  m  MO  •  2  (9  R203  •  20  Si02)  •  n  H20, 

(b)  m  MO  •  2  (9  R203  -  20  Si02)  •  n  CaCO, 


SiO, 

A1,O3 

Fe,0s 

FeO 

MgO 

CaO 

K,0 

Na,O 

H,0 

NaCl 

CaCO, 

CO, 

a 

Total 

Theory 
XXVII 

43.54 
44.08 

33.50 

32.85 

z 

z 

1.09 
1.18 

9.14 
9.17 

2.56 
2.68 

4.49 
4.43 

5.88 
6.20 

— 

— 

— 

— 

100.00 
100.59 

Theory 
X 

42.78 
43.80 

32.72 
32.85 

z 

1.28 
1.07 

z 

20.46 
20.64 

— 

2.76 
2.57 

— 

— 

z 

— 

z 

100.00 
100.93 

Theory 
XCVIII 

38.94 
37.81 

24.83 
25.10 

7.78 
7.89 

— 

z 

19.07 
18.34 

7.63 
7.30 

1.75 
1.50 

z 

z 

z 

z 

100.00 
97.94 

Theory 
IX 

40.80 
40.80 

31.21 
30.60 

— 

- 

— 

22.37 
22.10 

z 

2.63 
2.40 

z 

- 

— 

2.99 
3.10 

z 

100.00 
100.00 

*  The  excess  above  100.00  in  the  Theory-Total  in  Nos.  64,  65  and  66  is  due  to  the  oxygen  - 
equivalent  of  the  chlorine  being  included  in  the  figures  in  the  Na20  column. — A.  B.  S. 


384 


THE   ORTHOCHLORITE    GROUP 


The 

The  following  analyses  of  the  minerals 


A.  Si  •  R  •  Si         =3  R203  •  10  SiO 


B.  Si  •  R  •  Si 

^xsl 

C.  Rf-Si 


=  3  R203  •  12  SiO 


2> 


2> 


3  R203  •  15  Si02, 


D. 


Ni 


E.  R  -  Si 

F.  Si-R 


R 
R 


=  3  R203  •  18  Si025 

=  5  R203  •    6  Si02, 
Si  =  5  R203  •  12  Si02, 


A.  Orthochlorites  of  the  type 
Si  •  R  •  Si  =  3  R203  •  10  Si02 


Source 

22  MO  •  2  (3  A1203  •  10  SiO2) 
•  16  H20 

31MO-2(3R203-10Si02) 
•  26  H2O 

32  MO    2  (3  R2O3  •  10  SiO2) 
•24H20 

34  MO  •  2  (3  A12O3  •  10  SiO2) 
•  26  H20 

43MO-2(3R2O3-10Si02) 
•8H2O 

22  MO  =  12.5  FeO  •  7  MgO  •  1  CaO 
•  0.5  MnO  •  0.5  K2O  •  0.5  Na2O 

31  MO  =  27  MgO  •  3.5  FeO  •  0.5  CaO  ; 
6R203  =  5Al203-lFe203 

32  MO  =  30  MgO  -2  FeO; 
6  R2O3=5.5  A12O3  •  0.5  Fe2O3 

34  MO  =  31  MgO  -3  FeO 

43  MO  =  40.5  MgO  •  2.5  FeO  ; 
6  R2O3=5  A12O3  •  1  Cr2O3 

Ortho- 
chlorite 

Delessite 

Orthochlorite 
(Clinochlorite) 

Orthochlorite 

M 

Bishops  Hill 

St.  Cyrus, 
Scotland 

Kupferberg 
Zillertal 

Webster, 

N.C. 

B.  Orthochlorites  of  the  types 
Si  •  R  •  Si  =  3  R203  •  12  Si02 

Source 

6 

25  MO- 

2  (3  R203  - 

12  Si02) 

25  MO  =  25  MgO 

Lennilite 

Petham, 

-  * 

22H2O 

6R203  =  5Al203-lFe2O3 

Mass. 

7 

33  MO- 

2  (3  R203  • 

12Si02) 

33  MO  =  19MgO-6FeO-7CaO-lK2O 

Orthochlorite 

Corry- 

• 

28H20 

6  R2O3  =  5.5  A12O3  •  0.5  Fe2O3 

(Pennine) 

charmaig 

8 

33  MO- 

2  (3  R2O3  • 

12  Si02) 

33  M0  =  31  MgO  •  1  FeO  •  1  CaO 

Orthochlorite 

Bissersk 

28H2O 

6  R2O3  =  5.5  A12O3  •  0.5  Cr2O3 

9 

36  MO- 

2  (3  A1203  - 

12  SiO2) 

36  MO  =  31.5  MgO  •  1.5  FeO-1.5  K2O 

w 

Tilly  Foster 

• 

24H20 

•!Na2O-0.5Li2O 

Mine,  N.Y. 

10 

38  MO  • 

2  (3  R203  • 

12  SiO2) 

38  MO  =  37  MgO  -1  FeO 

>» 

Itkul  Sea 

• 

28H20 

6  R2O3  =  4.5  A12O3  •  1.5  Cr2O3 

11 

38  MO- 

2  (3  R2O3  • 

12  Si02) 

38  MO  =  38  MgO 

M 

Calumet 

38H2O 

6  R2O3  =  5.5  A12O3  •  0.5  Fe2O3 

Falls,  Can. 

12 

39  MO- 

2  (3  R203  • 

12  SiO2) 

39  MO  =  39  MgO 

»> 

Texas,  Pa. 

.  • 

30H20 

6  R2O3=4.5  A12O3-0.5  Fe2O3-  1  Cr2O3 

THE   ORTHOCHLORITE   GROUP 

Orthochlorite  Group 

of  the  orthochlorite  group  conform  to  the  following  types  : 


385 


G.  Si  •  R  •  Si  •  R  •  Si 


H.  Si  •  R  •  Si 
J.  R-Si-R 

JA..     fel    *    -LV    *    _tv 


Si  •  R  •  Si  = 

m 

L.  Si  •  R  •  R  •  Si 
M.  Si  •  R  •  Si  •  R  •  Si 

N.  Si-R-iSi-R-Si        = 
0.  R  •  Si  •  R  •  SAi  •  R 
P.  R  •  SAi  •  R  •  Si  -  R 


5R203 

•  18  Si02, 

5R203 

•22Si02, 

6R203 

•    6Si02, 

6R203 

•  10  Si02, 

6R203 

•  12  Si02, 

6R203 

•  16  SiOa, 

6R203 

•  18  Si02, 

8R203 

•  12  SiO2, 

9  R20a 

•  12  SiO* 

or  the  general  formula 

m  MO  •  2  (3  R203  •  10  Si02)  •  n  H20. 


Analyst 

Si02 

A1208 

Fe203 

Crz03 

FeO 

MnO 

CaO 

MgO 

K,0 

Na2O 

H20 

Total 

Heddle 

Theory 
LXIX 

34.89 
35.41 

17.79 

18.08 

0.48 

z 

26.16 
26.47 

1.03 

0.61 

1.34 
1.01 

8.14 
8.77 

1.37 
0.98 

0.90 
0.52 

8.38 
8.03 

100.00 
100.36 

» 

Theory 
V 

32.45 
32.69 

13.79 
13.44 

4.33 
4.40 

— 

6.81 
6.62 

z 

0.76 
0.86 

29.20 

28.77 

z 

— 

12.66 
13.25 

100.00 
100.03 

Kobell 

Theory 
III 

33.17 
33.49 

15.51 
15.37 

2.23 
2.30 

0.55 

3.98 
4.25 

— 

— 

33.17 
32.94 

— 

— 

11.94 
11.50 

100.00 
100.40 

Briiel 

Theory 
XXIII 

32.12 
31.47 

16.38 
16.67 

~ 

— 

5.78 
5.97 

0.11 

— 

33.19 
32.56 

— 

— 

12.53 
12.43 

100.00 

99.21 

Genth 

Theory 
CLX 

31.53 
31.45 

13.40 
13.08 

— 

3.99 
4.16 

4.74 

4.88 

— 

0.17 

42.56 
43.10 

0.06 

0.16  NiO 

3.78 
3.29 

100.00 
100.35 

or  the  general  formula 

m  MO  •  2  (3  R203  •  12  Si02)  •  n  H20. 


Analyst 

SiOa 

A1203 

Fe20s 

Cr208 

FeO 

MnO 

CaO 

MgO 

K,0 

NajO 

H20 

Total 

Gooch 

Theory 
III 

41.07 
41.27 

14.55 
15.19 

4.56 
4.14 

— 

— 

— 

— 

28.53 

28.25 

— 

— 

11.09 
11.32 

100.00 
100.17 

Heddle 

Theory 
LXII 

33.78 
34.31 

13.16 
13.64 

1.88 
0.36 

z 

10.13 
10.31 

0.23 

9.19 
8.97 

17.83 
18.14 

2.20 
1.36 

0.13 

11.83 
12.41 

100.00 
99.76 

Hartwall 

Theory 
CXI 

36.83 
37.00 

14.36 
14.20 

— 

1.94 
1.00 

1.84 
1.50 

1.43 
1.50 

30.69 
31.50 

z 



12.91 
13.00 

100.00 
99.70 

Schlaepfer 

Theory 
CXXVII 

35.38 
36.18 

15.04 
14.34 

0.28 

z 

2.65 

2.88 

0.38  Li2O 
0.42  Li20 

30.95 
31.26 

3.46 
3.09 

1.52 
1.99 

10.62 
10.31 

100.00 
100.75 

Hermann 

Theory 
CXIII 

34.42 
34.64 

10.97 
10.50 



5.46 
5.50 

1.72 
2.00 

~ 



35.38 
35.47 



— 

12,05 
12.03 

100.00 
100.14 

Hunt 

Theory 
CXVIII 

33.61 
33.28 

13.09 
13.30 

1.87 
1.92 

— 

— 

- 

- 

35.47 
35.50 

- 

— 

15.96 
16.00 

100.00 
100.00 

Smith  und 
Brush 

Theory 
CXLIV 

34.03 
33.26 

10.84 
10.69 

1.89 
1.96 

3.60 

4.78 

— 

— 

— 

36.87 
35.93 

- 

0.35 

12.77 
12.64 

100.00 
99.61 

2  c 


386 


THE   ORTHOCHLORITE   GROUP 


Source 

13 

39  MO  •  2  (3  R2O3 
•  30  H2O 

•12Si02) 

39  MO  =  39  MgO 
6  R2O3  =  4.5  A12O3-0.5  Fe2O3-  !Cr2O3 

Orthochlorite 

Texas,  Pa. 

14 

39  MO  •  2  (3  R2O3 
•32H20 

•12SiOa) 

39  MO  =  37  MgO  -2  FeO 
6  R2O3=5.5  A12O3  -0.5  Fe2O3 

»» 

Zillertal 

15 

39  MO  •  2  (3  R2O3 
-      •  32  H2O 

-12Si02) 

39  MO  =  37  MgO  -2  FeO 
6  R2O3  =  5.5  A12O3  •  0.5  Fe,O3 

" 

»« 

16 

39  MO  •  2  (3  R2O3 
•  32  H2O 

•  12  SiO2) 

39  MO  =  37  MgO  -2  FeO 
6  R2O3  =  5.5  A12O3  •  0.5  Fe2O3 

« 

NaBfeld 

17 

39  MO  •  2  (3  R203 
•  32  H20 

•  12  SiO2) 

39  MO  =  37  MgO  -2  FeO 
6  R2O3  =  5.5  A12O3  •  0.5  Fe2O3 

99 

Zermatt 

18 

39MO-2(3R203 
•  32  H20 

•12Si02) 

39  MO  =  37  MgO  -2  FeO 
6  R2O3=5.5  A12O3  •  0.5  Fe2O3 

99 

'» 

19 

39  MO  •  2  (3  R203 
•  32  H20 

•12Si02) 

39  MO  =  37  MgO  -2  FeO 
6  R203=5.5  A1203  •  0.5  Fe2O3 

99 

» 

20 

40  MO  •  2  (3  A12O3 
•  30  H2O 

•  12  SiO2) 

40  MO  =  37  MgO  -3  FeO 

» 

Binnenthal 

21 

40  MO  -  2  (3  A12O3 
•  30  H2O 

•12SiO2) 

99              »             » 

99 

Zermatt 

22 

40  MO  •  2  (3  A1203 
•  30  H20 

•  12  SiO2) 

99              99            » 

99 

» 

23 

40MO-2(3A12O3 
•  30  H20 

•  12  SiO2) 

99              99            99 

99 

» 

24 

40  MO  •  2  (3  R2O3 
•30H20 

•  12  SiOa) 

40  MO  =  38.5  MgO  •  1.5  MnO 
6  R2O3  =  5.5  A1203  •  0.5  Fe2O3 

9* 

Pojsberg 

25 

43  MO  •  2  (3  A12O3 
•  30  H2O 

•12Si02) 

43  MO  =  25.5  MgO  •  17.5  FeO 

Diabantite 

Landes- 
freude 

26 

45  MO  •  2  (3  R2O3 
•  30H2O 

•12SiO2) 

45  MO  =  36MgO-7FeO-l  MnO-lNa2O 
6  R2O3  =  5  A12O3  -  1  Fe2O3 

Orthochlorite 

Sealpay 

C.  Orthochlorites  of  the  type 

/Si 

R^-Si  =  3  R203  •  15  Si02 

Source 

27 

32  MO  •  2  (3  A12O3  •  15  SiO2)  •  42  H2O 

32MO  =  29MgO-3FeO 

Orthochlorite 

North 

Burgess,  Can. 

28 

32  MO  •  2  (3  R2O3  •  15  SiO2)  •  54  H2O 

32  MO  =  32  MgO 

99 

Culsagee 

6R2O3  =  5Al2O3-lFe2O3 

Mine,  N.C. 

29 

99                               99                               99                                    99 

32  MO  =  32  MgO 

99 

99 

6R203=5Al203-lFe203 

30 

39  MO  •  2  (3  A1203  •  15  SiO2)  •  20  H2O 

39  MO  =  32  MgO  -7  FeO 

99 

Traversella 

31 

48  MO  •  2  (3  A1203  •  15  SiO2)  •  38  H2O 

48  MO  =  44  MgO 

99 

Beautyhill 

•2  FeO  •  1  CaO  -  1  MnO 

32 

53  MO  •  2  (3  A1203  •  15  SiO2)  •  36  H2O 

53  MO  =47  MgO  -6  FeO 

99 

Zermatt 

33 

„ 

»»                                      99                            99 

99 

»' 

THE   ORTHOCHLORITE   GROUP 


387 


Analyst 

SiO, 

A120, 

FeaO, 

Cr,Os 

FeO 

MnO 

CaO 

MgO 

K,0 

Na,0 

H,0 

Total 

Smith  and 

Theory 

34.03 

10.84 

1.89 

3.60 







36.87 





12.77 

100.00 

Brush 

CXLV 

33.30 

10.50 

1.60 

4.67 

— 

— 

— 

36.08 

0.35  Alk 

— 

13.25 

99.75 

Rumpf 

Theory 

33.60 

13.10 

1.83 

— 

3.36 

— 

— 

34.57 





13.48 

100.00 

XXIV 

34.24 

12.64 

1.64 

— 

3.35 

— 

0.30 

34.86 

— 

— 

14.44 

101.15 

Ludwig 

Theory 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 





XXV 

33.83 

12.95 

2.25 

— 

3.02 

— 

— 

34.94 

— 

— 

13.11 

100.10 

Telek 

Theory 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 





XXI 

33.44 

13.72 

3.40 

— 

3.26 

— 

— 

32.99 

— 

— 

12.71 

99.52 

Schlaepfer 

Theory 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 





XLVII 

34.06 

11.75 

1.92 

0.69 

2.78 

— 

— 

33.90 

0.39 

2.45 

13.08 

101.02 

v.  Fellenberg 

Theory 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

XLIV 

33.12 

13.25 

1.52 

0.60 

4.69 

— 

— 

34.04 

— 

— 

12.87 

100.09 

v.  Hamm 

Theory 

























XLVI 

33.71 

12.55 

2.74 

— 

3.40 

— 

0.66 

34.70 

— 

— 

12.27 

100.03 

Marignac 

Theory 

33.58 

14.27 

— 

— 

5.04 

— 

— 

34.52 

— 

— 

12.59 

100.00 

XLVIII 

33.95 

13.46 

0.24 

6.12 

— 

— 

33.71 

— 

— 

12.52 

100.00 

» 

Theory 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

XXXVIII 

33.36 

13.24 

— 

0.20 

5.93 

— 

— 

34.21 

— 

— 

12.80 

99.74 

» 

Theory 

33.58 

14.27 

— 

— 

5.04 

— 

— 

34.52 

— 

— 

12.59 

100.00 

XXXIX 

33.40 

13.41 

— 

0.15 

5.73 

— 

— 

34.57 

— 

— 

12.74 

100.00 

Wartha 

Theory 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

XLIII 

32.51 

14.55 

— 

— 

4.96 

— 

— 

34.01 

— 

— 

14.07 

100.10 

Hamberg 

Theory 

33.73 

13.14 

1.87 



2.53 

__ 



36.08 





12.65 

100.00 

LXXXVIII 

33.71 

13.80 

1.64 

— 

2.28 

— 

— 

35.88 

— 

— 

13.11 

100.75 

Liebe 

Theory 

29.56 

12.57 

— 

— 

25.86 



— 

20.94 

— 

— 

11.08 

100.00 

II 

29.37 

12.00 

— 

— 

25.63 

— 

0.33 

21.01 

— 

— 

11.27 

99.28 

Heddle 

Theory 

30.40 

10.77 

3.38 



10.60 

1.50 

— 

30.40 

— 

1.52 

11.43 

100.00 

LXI 

30.41 

11.58 

2.34 

— 

10.71 

1.19 

— 

30.63 

0.01 

1.31 

11.74 

99.92 

or  the  general  formula 

m  MO  •  2  (3  R203  •  15  Si02)  •  n  H20. 


Analyst 

SiO, 

Al,03 

Fe20, 

Crz03 

FeO 

MnO 

CaO 

MgO 

K,O 

NazO 

HaO 

Total 

Hunt 

Theory 

39.61 

13.47 





4.75 

25.53 









16.64 

100.00 

cxx 

39.30 

14.25 

— 

— 

4.41 

25.73 

— 

— 

— 

— 

16.93 

100.62 

Chatard 

Theory 

38.12 

10.80 

3.38 

— 



— 

— 

27.12 

— 

— 

20.58 

100.00 

CLVIII 

38.29 

11.41 

1.95 

— 

0.32 

0.25(Ni,  Cop 

— 

26.40 

— 

— 

21.25 

99.87 

Clarke  & 

Theory 

38.12 

10.80 

3.38 

— 

— 

— 

— 

27.12 

— 

— 

20.58 

100.00 

Schneider 

CLIX 

38.13 

11.22 

2.28 

— 

0.18 

0.48  NiO 

— 

27.39 

— 

— 

20.47 

100.15 

Marignac 

Theory 

39.51 

13.44 

— 

— 

11.06 

— 

— 

28.09 

— 

— 

7.90 

100.00 

LIV 

39.81 

12.56 

— 

— 

11.10 

— 

— 

28.41 

— 

— 

7.79 

99.67 

Heddle 

Theory 

35.11 

11.94 





2.81 

1.38 

1.09 

34.33 

— 

— 

13.34 

100.00 

LXV 

34.73 

12.44 

— 

— 

2.68 

1.17 

1.60 

34.10 

— 

— 

13.10 

99.82 

Max 

Theory 

33.51 

11.39 

— 

— 

8.01 

— 

— 

35.00 

— 

— 

12.09 

100.00 

Donnell 

XL 

33.64 

10.64 

— 

— 

8.83 

— 

— 

34.95 

— 

— 

12.40 

100.46 

Merz 

Theory 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

XLI 

33.26 

11.69 

— 

— 

7.20 

— 

— 

35.18 

— 

— 

12.18 

99.51 

388 


THE   ORTHOCHLORITE   GROUP 

D.  Orthochlorites  of  the  type 

Rr-SAi  =  3  R203  •  18  Si02 
XSi 


Source 

34 

46  MO 

•2(3A12O3 

•18SiO2)- 

22H2O 

46  MO  =39  MgO  -7  FeO 

Orthochlorite 

Traversella 

35 

36 

48  MO 
50  MO 

•2(3A1203 
•2(3A1203 

•  18  SiO2)  - 
•18S10,)- 

24H2O 
26H2O 

48MO=35MgO-6FeO-3CaO 
•3  Na2O  •  1  K2O 

50MO=40MgO-10FeO 

» 

Hillswick 
Traversella 

37 

38 

50  MO 
59  MO 

•2(3A1203 
•2(3A1203 

•18SiO2)- 
•  18  SiO2)  • 

46H20 
64H2O 

50  MO  =  42  MgO  -8  FeO 
59  MO  =  32.5  MgO-26.5FeO 

»> 
Diabantite 

North  Elms- 
ley,  Can. 

Holletal 

39 

63  MO 

•2(3A1203 

•  18  SiO2)  • 

44H2O 

63  MO  =  53  MgO  -10  FeO 

Orthochlorite 

Zermatt 

40 

» 

» 

» 

ft 

j>                 ?»             » 

>» 

» 

E.  Orthochlorites  of  the  type 
R  •  SAi  •  R  =  5  R203  •  6  Si02 


Source 

41 

24  MO  •  2  (5  A12O3  •  6  SiO2  •  20  H2O 

24MO  =  16.5MgO-7.5FeO 

Orthochlorite 

Chester, 
Mass. 

F.  Orthochlorites  of  the  type 
Si  •  R  •  R  •  Si  =  5  R203  •  12  Si02 


Source 

42 

12MO-2(5R203-12SiO2) 
•28H20 

12  MO  =  8MgO-2.5CaO-lMnO-0.5K80 
•10  R2O3=6.5  A12O3  •  3.5  Fe2O3 

Hullite 

Kinkell 

43 

22MO-2(5Al203-12Si02 
•24H20 

22  MO  =  21  MgO  •  0.5  CaO  •  0.5  FeO 

Orthochlorite 

Markirch 

44 

29MO-2(5R203-12SiO2 
•38  H20 

29MO  =  29FeO 
10  R2O3=  9  A12O3  •  1  Fe2O3 

Chamosite 

Schmiedefeld 

45 

33MO-2(5R2O3-12SiO2) 
•32H20 

33  MO  =  17.5  MgO-  11  FeO  •  4.5  CaO 
10R203  =  7Al203-3Fe203 

Chloropite 

Chloropitschiefer 
von  Koditz 

46 

34MO-2(5R2O3-12SiO2) 
•34  H2O 

34  MO  =  20.5  MgO  •  12.5  FeO  •  1  CaO 
10  R2O3  =  8,5  A12O3  •  1.5  Fe2O3 

Delessite 

Friedrichsroda 

47 

36  MO-2(5  Al2O3-12SiO2) 
•36  H2O 

36  MO  =  33  FeO  •  3  MgO 

Chamosite 

Chrustenic 

48 

38  MO-2(5  Al2O3-12SiO2) 
•32H20 

38  MO  =  35  MgO  -3  FeO 

Orthochlorite 

Newlin,  Pa. 

49 

40MO-2(5R2O3-12SiO2) 
•32  H2O 

40  MO  =  40  MgO 
10  R2O3  =  8.5  A12O3  •  1.5  Fe2O3 

?> 

Alatal 

50 

40MO-2(5R203-12Si02) 
•32H2O 

40  MO  =  40  MgO 
10  R2O  =  8.5  A12O3  •  1.5  Fe2O3 

» 

Achmatowsk 

THE   ORTHOCHLORITE   GROUP 


389 


or  the  general  formula 


m  MO  •  2  (3  R2O3  •  18  Si02)  •  n  H20. 


Analyst. 

SiOa 

Al2os 

FeaOi  1  Cr20j  |    FeO 

MnO 

CaO 

MgO 

K«0 

Na,0 

H,0 

Total 

Marignac 

Theory 
LV 

41.28 
41.34 

11.70 
11.42 

~ 

~ 

9.63 
10.09 

— 



29.82 
29.67 

— 

~ 

7.57 

7.66 

100.00 
100.18 

Heddle 

Theory 
LXXVIII 

39.39 
39.81 

11.16 
11.43 

~ 

~ 

7.88 
7.97 

0.26 

3.06 

2.80 

25.53 
25.65 

1.71 
1.20 

3.39 
3.15 

7.88 
7.91 

100.00 
100.18 

Marignac 

Theory 
LIII 

38.84 
38.45 

11.01 
11.75 

~ 

~ 

12.94 
12.82 

~ 



28.76 
28.19 

__ 

— 

8.45 
8.49 

100.00 
99.70 

Hunt 

Theory 
CXIX 

36.88 
36.70 

10.45 
10.96 

— 

~ 

9.84 
9.36 

— 



28.69 
28.19 





14.14 
14.31 

100.00 
99.52 

Liebe 

Theory 
V 

30.29 

29.85 

8.58 
9.07 

~ 

~ 

26.75 
26.60 

— 

— 

18.23 
17.92 





16.15 
15.81 

100.00 
99.25 

Schweizer 

Theory 
XXXVI 

33.73 
33.82 

9.56 
9.32 

~ 

~ 

11.24 
11.30 

- 

__ 

33.10 
33.04 

— 

__ 

12.37 
11.50 

100.00 
98.98 

»» 

Theory 
XXXVII 

33.07 

9.69 





11.36 





32.34 





12.58 

99.04 

or  the  general  formula 

m  MO  •  5  (5  R203  •  6  Si02)  •  n  H20. 


Analyst 

Si02 

A1.0, 

Fe208 

Cr203 

FeO 

MnO 

CaO 

MgO 

K20 

Na20 

H20 

Total 

Pisani 

Theory 
CXXIV 

21.81 
21.40 

30.91 
32.30 

— 

— 

16.36 
15.80 

— 

— 

20.00 
19.90 

— 

— 

10.91 
10.90 

100.00 
100.30 

or  the  general  formula 
mMO  •  2(5R203-  12S10, 


nH20. 


Analyst 

Si02 

A1203 

Fe203 

Cr20s 

FeO 

MnO 

CaO 

MgO 

K20       |Na2o|    H20 

Total 

Heddle 

Theory 
II 

38.45 
38.59 

17.71 
17.34 

14.95 
15.97 

— 

— 

1.90 
1.56 

3.74 
3.94 

8.54 
8.65 

1.25 
0.67 

- 

13.46 
13.48 

100.00 
100.20 

Delesse 

Theory 

37.94 
38.39 

26.87 
26.54 

— 

— 

0.94 
0.59 

z 

0.74 
0.67 

22.13 
22.16 

z 

- 

11.38 
11.65 

100.00 
100.00 

Loretz 

Theory 
III 

27.22 
27.00 

17.35 
17.00 

3.02 
4.00 

— 

39.47 
39.00 

z 

z 

z 

~ 

— 

12.94 
13.00 

100.00 
100.00 

»> 

Theory 
IV 

29.07 
29.06 

14.41 
14.04 

9.69 
9.27 

- 

15.99 
15.96 

— 

5.08 
5.02 

14.13 
13.95 

— 

— 

11.63 
11.64 

100.00 
98.94 

Pufahl 

Theory 
IV 

29.18 

28.79 

17.57 
16.74 

4.86 
4.83 

— 

18.24 
18.30 

- 

1.13 

0.98 

16.61 
16.62 

— 



12.41 
12.25 

100.00 
100.21 

Boricky 

Theory 
VI 

25.69 
25.60 

18.20 
18.72 

— 

— 

42.40 
42.31 

- 

— 

2.14 
2.13 

— 

- 

11.57 
11.24 

100.00 
100.00 

Leeds 

Theory 
CXXXVII 

30.96 
30.62 

21.92 
21.73 

0.42 

~ 

4.64 
5.01 



— 

30.09 
29.69 

0.11Li2O 

0.14 

12.39 
12.26 

100.00 
99.98 

Marignac 

Theory 
L 

30.49 
30.01 

18.36 
19.11 

5.08 
4.81 

— 





— 

33.88 
33.15 

__ 



12.19 
12.52 

100.00 
99.60 

'» 

Theory 
XCI 

30.49 
30.27 

18.36 
19.85 

5.08 

4.42 

— 

- 

— 

- 

33.88 
33.13 

— 

~ 

12.19 
12.54 

100.00 
100.25 

390 


THE   SCAPOLITE   GROUP 


Source 

51 

40  MO  •  2(5  A12O3  •  12  SiO2) 
•32H20 

40  MO  =  23.5  MgO  •  16.5  FeO 

Orthochlorite 

Gumuch,  Dagh. 

52 

40  MO  •  2(5  A12O3  •  12  SiO2) 
•34H20 

40  MO  =  22  MgO-  18  FeO 

» 

Sept-Lacs 

53 

40  MO  •  2(5  R2O3  •  12  SiO2) 

40  MO  =  38  MgO  -2  FeO 

Jf 

Borostyanko 

•  34  H2O 

10R2O3=9Al203-lFe2O3 

54 

40  MO  •  2(5  A12O3  •  12  SiO2) 

40  MO  =  38  MgO  -2  FeO 

99 

Alatal 

•  40  H2O 

55 

40  MO  •  2(5  A1203  •  12  SiO2) 

»             »             »> 

»> 

,, 

•  40  H2O 

56 

41  MO  -  2(5  R2O3  •  12  SiO2) 

41  MO  =  37  MgO  -4  FeO 

M 

Montafun 

•34H20 

10  R2O3=9.5  A12O3  •  0.5  Fe2O3 

57 

41  MO  •  2(5  A12O3  •  12  SiO2) 
•46H20 

41MO  =  34FeO-5MgO-  1  CaO 
•1K20 

Metachlorite 

Buchenberge 
bei  Elbingerode 

58 

42  MO  •  2(5  A12O3  •  12  SiO2) 

42  MO  =  38  MgO  •  4  FeO 

Orthochlorite 

Culsagee  Mine, 

•  32  H2O 

N.C. 

59 

42MO-2(5Al2O3-12Si02) 

42MO  =  41.5MgO-0.5FeO 

» 

Amity,  N.Y. 

•34H20 

60 

42MO-2(5Al203-12Si02) 

42  MO  =  21  MgO  -20  FeO 

M 

Foundry  Run, 

•46H20 

-  1  Na20 

Georget,  D.C. 

61 

46  MO  •  2(5  A12O3  •  12  SiO2) 

46  MO  =  24  MgO  •  22  FeO 

M 

St.  Gotthard 

•  28  H2O 

62 

46  MO  •  2(5  A12O3  •  12  SiO2) 

46  MO  =  33  MgO  •  12  FeO  •  1  CaO 

>» 

Zillertal 

•  38  H2O 

63 

47MO-2(5R2O3-12Si02) 

47  MO  =  33.5MgO-12.5FeO-lMnO 

>f 

Loch  Laggan 

•36H20 

10  R2O3  =  9.5  A1203  •  0.5  Fe2O3 

G.  Orthochlorites  of  the  type 
Si  •  E  •  Si  •  R  •  SAi  =  5  R203  •  18  Si02 


Source 

64 

42  MO 

•  2(5  R2O3  • 
•  36  H20 

18  Si02) 

42  MO  =  42  MgO 
10  R2O3  =  7.5  A12O3  •  2.5  Fe2O3 

Lennilite 

Lenni 

65 

44  MO 

•  2(5  R203  • 
•34H20 

18SiO2) 

44  MO  =  37.5  MgO  •  3.5  FeO  •  3  CaO 
10  R2O3  =  7.5  A12O3  •  2.5  Fe2O3     &? 

Berlauite 

Berlaubach 
bei  Budweis 

66 

44  MO 

•2(5R203- 
•  40  H20 

18  SiO2) 

44  MO  =  28.5MgO  •  14  FeO  •  1.5  CaO 
10  R2O3=7.5  A12O3  •  2.5  Fe2O3 

Euralite 

Kiperjarvi 

67 

44  MO 

•  2(5  R203  • 
•  58  H2O 

18  SiO3) 

44  MO  =  37.5  MgO  •  3.5  FeO  •  3  CaO 
10  R203  =  7.5  A1203  •  2.5  Fe2O3       .,  [ 

Berlauite 

Berlaubach 
bei  Budweis 

68 

53  MO 

•  2(5  R203  • 
•  48  H20 

18Si02) 

53  MO  =  53  MgO 
10  R2O3  =  7  A12O3  •  3  Fe2O3 

Ortho- 
chlorite 

Snarum 

69 

54  MO 

-  2(5  A1203  • 
•  48  H2O 

18  SiO2) 

54  MO  =  53  MgO-  1  FeO 

» 

Ploben 

70 

56  MO 

•  2(5  R203  • 
•  54  H2O 

18  SiO2) 

56  MO  =  33  MgO  •  18  FeO  •  2  CaO  -1  MnO 
•1.5Na2O-0.5K2O;10R2O3  =  9Al2O3-lFe2O3 

Delessite 

Elie,  Fife- 
shire 

71 

57  MO 

•2(5R2O3- 
•  48  H2O 

18  SiO2) 

57  MO  =  57  MgO 
10  R2O3=7  A12O3  •  2.5  Cr2O3  •  0.5  Fe2O3 

Ortho- 
chlorite 

Texas,  Pa. 

72 

57  MO 

•2(5R203- 
"-.48  H2O 

18.Si08) 

57  MO  =  57  MgO 
10  R2O3  =  7  A12O3  •  2.5  Cr2O3  •  0.5  Fe2O3 

n 

»         »» 

THE   ORTHOCHLORITE   GROUP 


391 


Analyst 

Si02 

A1203 

Fe208 

Cr203 

FeO 

MnO 

CaO 

MgO 

K2O 

Na20 

H20 

Total 

L.  Smith 

Theory 

27.88 

19.75 



— 

23.01 

— 

— 

18.21 





11.15 

100.00 

CXIV 

27.20 

18.62 

— 

— 

23.21 

— 

— 

17.64 

— 

— 

10.61 

97.28 

Marignac 

Theory 

27.44 

19.44 

— 

— 

24.70 

— 

— 

16.77 

— 

— 

11.65 

100.00 

LX 

27.14 

19.19 

— 

— 

24.76 

— 

— 

16.78 

— 

— 

11.50 

99.37 

Szilasi 

Theory 

30.04 

19.15 

3.34 

— 

3.00 

— 

— 

31.71 

— 



12.76 

100.00 

XVI 

30.45 

18.96 

3.70 

— 

2.21 

— 

— 

32.20 

— 

— 

12.79 

100.31 

Jannasch 

Theory 

29.73 

21.06 



— 

2.97 

— 

— 

31.37 

— 



14.87 

100.00 

LI 

29.31 

21.31 

0.07 

— 

3.24 

— 

— 

31.28 

— 

0.43 

14.58 

100.22 

Theory 



LII 

29.59 

24.82(Al2O3+FeO) 

— 

— 

— 

31.46 

— 

0.30 

14.73 

100.90 

Wartha 

Theory 

29.57 

19.91 

1.64 

— 

5.91 

— 

— 

30.41 

— 

— 

12.56 

100.00 

XXXII 

29.44 

20.98 

2.00 

— 

5.60 

— 

— 

30.31 

— 

— 

12.29 

100.62 

List 

Theory 

23.65 

16.76 

— 

— 

40.22 



0.93 

3.28 

1.55 



13.61 

100.00 

I 

23.78 

16.43 

— 

— 

40.37 

— 

0.74 

3.10 

1.38 

0.08 

13.76 

99.64 

Genth 

Theory 

29.73 

21.06 



— 

5.94 



— 

31.38 





11.89 

100.00 

CLVI 

29.48 

22.22 

0.70 

— 

5.30 

0.17 

— 

30.99 

0.11(]S 

iCo)O 

11.63 

100.60 

Sipocz 

Theory 

30.20 

21.40 

— 

— 

0.76 

— 

— 

34.81 

— 

— 

12.83 

100.00 

cxxv 

30.28 

22.13 

— 

— 

1.08 

— 

— 

34.45 

— 

— 

12.61 

100.55 

Clarke 

Theory 

25.57 

18.11 





25.57 



— 

14.92 



1.09 

14.70 

100.00 

CLI 

25.45 

17.88 

— 

— 

24.98 

— 

— 

15.04 

— 

0.67 

14.43 

98.45 

Varren- 

Theory 

26.14 

18.52 





28.76 





17.43 

— 



9.15 

100.00 

trapp 

XXXIII 

25.37 

18.50 

— 

— 

28.79 

— 

— 

17.09 

— 

8.96 

98.71 

Tscher- 

Theory 

26.69 

18.91 

— 

— 

16.02 

— 

1.04 

24.47 

— 

— 

12.87 

100.00 

mak 

XXXI 

26.30 

19.80 

— 

— 

15.10 

— 

1.00 

24.40 

— 

— 

12.40 

99.00 

Heddle 

Theory 

26.42 

17.79 

1.47 



16.52 

1.30 



24.59 





11.91 

100.00 

LXXV 

26.25 

19.22 

1.67 

— 

16.44 

1.02 

— 

24.35 

— 

— 

11.67 

100.62 

or  the  general  formula 

m  MO  •  2  (5  R2O3  •  18  Si02)  •  n  H20. 


Analyst 

Si02 

A1208 

Fe203 

Cr2O8 

FeO 

MnO 

CaO 

MgO 

K20 

Na20 

H20 

Total 

Gooch 

Theory 
II 

38.21 
38.03 

13.53 
12.93 

7.08 
7.02 

— 

0.50 

— 

— 

29.72 
29.64 

— 

— 

11.46 
11.68 

100.00 
99.80 

Schrauf 

Theory 
II 

36.88 
37.25 

13.05 
13.75 

6.83 
6.86 

~ 

4.31 
4.02 

z 

2.86 
2.81 

25.62 
25.77 





10.45 
9.82 

100.00 
100.28 

Wilk 

Theory 

34.41 
33.68 

12.18 
12.15 

6.37 

6.80 

— 

16.06 
15.66 

— 

1.34 
1.34 

18.16 
17.92 

z 

- 

11.48 
11.49 

100.00 
99.04 

Schrauf 

Theory 

34.35 
34.38 

12.16 
12.69 

6.36 
6.33 

— 

4.00 
3.71 

- 

2.67 
2.59 

23.85 
23.79 

z 

— 

16.61 
16.79 

100.00 
100.28 

Rammels- 
berg 

v.  Drasche 

Theory 
LXXIX 

Theory 
XII 

34.07 
34.88 
34.64 
34.63 

11.27 
12.48 

16.35 
17.13 

7.57 
5.81 

— 

1.14 
1.61 

— 

— 

33.45 
34.02 

34.00 
33.38 

— 

— 

13.64 
13.68 

13.87 
13.93 

100.00 
100.87 

100.00 
100.68 

Heddle 

Theory 
IX 

30.22 
30.69 

12.84 
12.83 

2.24 
1.63 

— 

18.14 
18.32 

0.99 
1.00 

1.56 
1.59 

18.46 
18.60 

0.65 
0.57 

1.30 
1.11 

13.60 
13.77 

100.00 
100.11 

Genth 

Theory 
CXLII 

33.34 
33.20 

11.02 
11.11 

1.24 
1.43 

5.88 
6.85 

— 

z 

z 

35.19 
35.54 

0.38  Alk 

z 

13.33 
12.95 

100.00 
101.46 

Dieffen- 
bach 

Theory 
CXLVI 

33.34 
33.04 

11.02 
11.09 

1.24 
1.33 

5.88 
5.91 

z 

— 

z 

35.19 
34.30 

0.38  Alk 

z 

13.33 
12.81 

100.00 
98.86 

392 


THE   ORTHOCHLORITE   GROUP 


Source 


73 

74 

75 
76 

77 
78 
79 


58MO-2(5Al203-18SiO2) 

•  48  H20 

60MO-2(5R203-18SiO2) 
•48H20 

61MO-2(5R2O3-18SiO2) 
•48H20 

61  MO  •  2(5  A12O3  •  18  SiO2) 
-44H20 

63MO-2(5R2O3-18SiO2) 

•  52  H2O 

63MO-2(5R203-18Si02) 

•  52  H2O 

65MO-2(5Al,03-18SiO2) 

•  44  H26 


58  MO  =  56  MgO -2  FeO 

60  MO  =  54  MgO  •  5  FeO  •  1  CaO 
10  R2O3  =  9  A12O3  •  1  Fe2O8 

61  MO  =  60 MgO-  IFeO 
10R2O3=5Al203-5Cr203 

61  MO  =  55  MgO -6  FeO 

63  M0  =  60  MgO  •  2  FeO  •  1  CaO 
10  R2O3  =  8.5  A12O3  •  1.5  Cr2O3 

63  MO  =  60  MgO  •  2  FeO  •  1  CaO 
10  R2O3=8.5  A12O3  -  1.5  Cr2O3 

65  MO  =  58  MgO  •  5  FeO  •  1  CaO 
•  0.5  K2O  •  0.5  Na2O 


Ortho- 
chlorite 


Zdjar-Berg 
Hillswick 

Green  Valley 
Cal. 

Zillertal 
Texas,  Pa. 


Tilly  Foster 
Mine,  N.Y. 


H.  Orthochlorites  of  the  type 

Si  •  R  •  Si  •  Si  •  R  •  Si  =  5  R203  •  22  Si02 


Source 

80 

42  MO  •  2(5  R2O3  •  22  SiO2) 

42  M0  =  33  MgO  •  8  FeO  •  1  CaO 

Epichlorite 

Harz 

•  36  H20 

10R2O3  =  6.5  A12O3  •  3.5  Fe2O3 

81 

46  MO  •  2(5  Fe2O3  •  22  SiO2) 

46  MO  =  46  FeO 

Cron- 

Pfibram 

•  50  H2O 

stedtite 

82 

51  MO  •  2(5  R2O3  •  22  SiO2) 

51  MO  =  48.5  MgO  •  2.5  FeO 

Lennilite 

Kremze 

•  48  H2O 

10R2O3  =  9Al203-lFe208 

83 

52MO-2(5R203-22Si02) 

52MO  =  44MgO-5CaO-2.5FeO-0.5  NiO 

Ortho- 

Texas,  Pa. 

•  52  H2O 

10  R2O3  =  8  A12O3  •  2  Cr2O3 

chlorite 

84 

60  MO  •  2(5  R203  •  22  SiO2) 

60  MO  =  51  MgO-3  K2O-3  FeO-3  Na2O 

w 

Taberg 

•24H20 

10  R2O3  =  8.5  A12O3  •  1.5  Fe2O3 

85 

60  MO  •  2(5  R2O3  •  22  SiO2) 

60  MO  =  32  MgO  •  27  FeO  •  1  CaO 

Diabantite 

Farmington 

•  44  H2O 

10  R2O3=  8.5  A12O3  •  1.5  Fe2O3 

Hills 

86 

60  MO  •  2(5  R2O3  •  22  SiO2) 

60  MO  =  32  MgO  -  27  FeO  •  1  CaO 

n 

n 

•  44  H2O 

10  R2O3  =  8.5  A12O3  •  1.5  Fe2O3 

87 

69  MO  •  2(5  R203  •  22  SiO2) 

69  MO  =  41.5  MgO  •  27.5  FeO 

99 

Trillochtal 

•  52  H20 

10R203=8Al203-2Fe203 

88 

72  MO  -2(5Al203-22Si02) 

72  MO  =  47  MgO  •  25  FeO 

99 

Landes- 

•  56  H20 

freude 

89 

72  MO  •  2(5  A12O3  •  22  SiO2) 

»»                 »»                 » 

M 

•  56  H2O 

90 

72  MO  •  2(5  A12O3  •  22  SiO2) 

»>                 »                 >» 

Grafenwart 

•  56  H2O 

91 

73  MO  •  2(5  A12O3  •  22  SiO2) 

73  MO  =  66  MgO  -7  FeO 

Ortho- 

Zermatt 

•  54  H2O 

chlorite 

92 

74  MO  •  2(5  R2O3  •  22  SiO2) 

74  MO  =  66  MgO  •  6  CaO  •  2  FeO 

99 

Unst 

•  64  H2O 

10R203  =  6Al203-4Cr203 

93 

75  MO  •  2(5  R2O3  •  22  SiO2) 

75  MO  =  73  MgO  -2  FeO 

Zermatt 

•  58  H2O 

10R2O3=9Al203-lFe203 

94 

79  MO  •  2(5  A12O3  •  22  SiO2) 

79  MO  =  46.5  MgO  •  32.5  FeO 

Diabantite 

Reinsdorf 

•  50  H2O 

THE   ORTHOCHLORITE   GROUP 


Analyst 

Si02 

AlaOs 

Fe203 

CTjOs 

FeO 

MnO 

CaO 

MgO 

K,0 

Na»o 

Hao 

Total 

K.v. 

Theory 

33.60 

15.87 

— 

— 

2.24 

— 

— 

34.85 

— 

— 

13.44 

100.00 

Hauer 

XIV 

33.51 

15.42 

— 

— 

2.58 

— 

— 

34.41 

— 

— 

13.21 

99.13 

Heddle 

Theory 

32.35 

13.76 

2.39 



5.39 



0.83 

32.34 





12.94 

100.00 

LXVIII 

32.55 

13.95 

0.97 

— 

5.28 

0.16 

0.79 

32.78 

0.48 

0.06 

13.17 

100.19 

Melville 

Theory 

31.92 

7.54 



11.25 

1.06 





35.46 





12.77 

100.00 

CLXII 

31.74 

6.74 

— 

11.39 

1.23 

•.  — 

0.18 

35.18 

0.49  NiO 

— 

13.04 

99.99 

Kobell 

Theory 

32.71 

15.44 





6.54 

— 

— 

33.32 





11.99 

100.00 

XXII 

32.68 

14.57 

— 

— 

5.97 

0.28 

— 

33.11 

1.02  Resid. 

— 

12.10 

99.73 

Pearse 

Theory 

31.71 

12.73 



3.33 

2.11 



1.12 

35.23 





13.75 

100.00 

CXLVII 

31.31 

12.84 

— 

2.98 

2.46 

— 

0.82 

35.02 

0.45  NiO 

— 

13.20 

99.08 

Pearse 

Theory 

31.71 

12.73 



3.33 

2.11 



1.12 

35.23 





13.75 

100.00 

CXLVIII 

31.86 

13.75 

— 

2.15 

2.31 

— 

1.27 

34.90 

0.22  NiO 

— 

13.98 

100.44 

Breiden- 

Theory 

31.83 

15.03 

— 

— 

5.30 

— 

0.82 

34.19 

0.69 

0.46 

11.68 

100.00 

baugh 

CXXVI 

32.33 

14.56 

— 

— 

5.29 

— 

1.04 

33.74 

0.87 

0.54 

12.02 

100.39 

or  the  general  formula 

m  MO  •  2  (5  R203  •  22  Si02)  •  n  H20. 


Analyst 

SiOa  |  Ala03 

FeaO, 

CTj03 

FeO 

MnO 

CaO  |  MgO 

KaO 

Na,0 

HaO 

Total 

Rammels- 
berg 

Theory 
I 

40.85 

40.88 

10.26 
10.96 

8.66 
9.72 

z 

8.91 
8.96 

- 

0.87 
0.68 

20.43 
20.00 

— 

Z 

10.02 
10.18 

100.00 
100.38 

Field 

Theory 
IX 

31.24 
31.72 

18.93 
18.51 

— 

39.19 
39.46 





— 





10.64 
11.02 

100.00 
100.71 

Schrauf 

Theory 

39.38 

38.88 

13.70 
13.45 

2.39 
3.22 

— 

2.68 
2.55 

- 

0.45 

28.95 
28.57 

— 

z 

12.90 
12.75 

100.00 
99.87 

Garret 

Theory 
CXLIII 

37.77 
37.66 

11.68 
11.82 

— 

4.35 
3.60 

2.57 
2.50 



4.01 
4.11 

25.17 

24.98 

1.06N1O 
0.67NiO 



13.39 
13.58 

100.00 
98.92 

Paltauf 

Theory 
LXXXVI 

38.24 
38.04 

12.56 
12.62 

3.48 
2.53 

~ 

3.13 
2.93 

0.51F1 

0.48 

29.55 
29.45 

4.09 
4.17 

2.69 
2.73 

6.26 
6.25 

100.00 
99.71 

Hawes 

Theory 
VIII 

33.76 
33.24 

11.08 
11.07 

3.07 
2.26 

— 

24.86 
25.11 

0.41 

0.72 
1.11 

16.37 
16.51 



0.25 

10.14 
9.91 

100.00 
99.87 

»» 

Theory 
IX 

33.76 
33.68 

11.08 
10.84 

3.07 
2.86 

— 

24.86 
24.33 

0.38 

0.72 
0.73 

16.37 
16.52 



0.33 

10.14 
10.02 

100.00 
99.69 

Liebe 

Theory 
VI 

31.61 
31.25 

9.77 
10.03 

3.83 
3.47 

z 

23.70 
23.52 

— 

- 

19.83 
19.73 





11.21 
11.37 

100.00 
99.37 

n 

Theory 
III 

31.63 
31.69 

12.22 
12.22 

— 

— 

21.56 
21.26 

— 

~ 

22.52 
22.05 

z 



12.07 
12.47 

100.00 
99.69 

» 

Theory 
IV 

31.63 
31.38 

12.22 
11.89 

— 

~ 

21.56 
22.72 

z 

z 

22.52 
22.91 



— 

12.07 
10.91 

100.00 
99.81 

" 

Theory 
VII 

31.63 
31.56 

12.22 
12.08 

— 

~ 

21.56 
21.61 

z 

— 

22.52 
22.44 





12.07 
11.78 

100.00 
99.47 

Piccard 

Theory 
XLII 

33.94 
33.54 

13.12 
13.39 

- 

~ 

6.49 
6.62 

z 

— 

33.94 
33.56 





12.51 
12.38 

100.00 
99.49 

Heddle 

Theory 
LXIV 

32.46 
32.31 

7.52 
7.50 

- 

7.49 
7.89 

1.77 

2.08 

z 

4.13 
3.83 

32.46 
32.15 

___ 

___ 

14.17 
14.25 

100.00 
100.01 

v.  Fellen- 

berg 

Theory 
XLV 

33.73 
33.97 

11.73 
11.66 

2.04 
2.49 

— 

1.84 
1.81 

— 



37.32 
37.60 

— 

— 

13.04 
13.57 

100.00 
101.10 

Liebe 

Theory 

30.14 
30.27 

11.64 
11.16 

. 

' 

26.70 
26.94 

- 



21.24 
21.22 





10.28 
10.20 

100.00 
99.79 

394 


THE   ORTHOCHLORITE    GROUP 


J.  Orthochlorites  of  the  type 
R  •  Si  •  R  =  6  R203  •  6  SiO2 


Source 

95 

18  MO 

•  2  (6  Fe203 
•  22  H2O 

•  6  Si02) 

18  MO  =  18  FeO 

Cron- 
stedtite 

Kuttenberg 

K.  Orthochlorites  of  the  type 
Si  •  R  •  R  •  Si  =  6  R203  •  10  Si02 


96 

Source 

16MO-2(6R2<V10SiO8) 

•  28  H20 

16  MO  =  16  MgO 
12  R203=9.5  A1203  •  2.5  Fe2O3 

Ortho 
chlorite 

Unionville 

97 

16MO-2(6R2O3-10SiO2) 
•  30  H2O 

16MO  =  16MgO 
12  R2O3=8  A12O3  •  4  Fe2O3 

» 

" 

98 

20MO-2(6R203-10Si02) 
•24H20 

20  MO  =  18  FeO-  1.5  MgO  •  0.5  CaO 
12  R2O3  =  8.5  A12O3  •  3.5  Fe2O3 

Aphro- 
siderite 

Konigshain 

99 

23  MO  •  2(6  R2O3  •  10  SiO2) 
•  26  H2O 

23  MO  =  17  MgO  •  5  FeO  •  1  K2O 
12R203=llAl203-lFe203 

Ortho- 
chlorite 

Unionville 

100 

23MO-2(6R2O3-10SiO2) 
•  26  H2O 

23  MO  =  17,MgO  -  SJFeO  •  1  K2O 
12R2O3=11A12O3-  !Fe2O3 

» 

»> 

101 

26  MO  •  2(6  R2O3  •  10  SiO2) 
•  30  H2O 

26  MO  =  24  FeO  -2  MgO 
12R203  =  8Al203-4Fe203 

Thuringite 

Harper's 

Ferry 

102 

26  MO  •  2(6  R2O3  •  10  SiO2) 
•  30  H2O 

26  MO  =  24  FeO  -2  MgO 
12R203=8Al203-4Fe2O3 

M 

Schmiede- 
feld 

103 

26  MO  •  2(6  R2O3  •  10  SiO2) 
•  30  H2O 

26  MO  =  23.5  FeO  •  2  MgO  •  0.5  Na2O 
12R203  =  8  A1203   4Fe203 

» 

Harper's 
Ferry 

104 

26  MO  •  2(6  R2O3  •  10  SiO2) 
•  30  H2O 

26  MO  =  23.5  FeO  •  2  MgO  •  0.5  Na2O 
12  R2O3=  8  A12O3  •  4  Fe2O3 

» 

»> 

105 

27  MO  •  2(6  Fe2O3  •  10  SiO2) 
•  24  H2O 

27  MO  =  19  FeO  •  7  MgO  •  1  MnO 

Cron- 
stedtite 

Pfibram 

106 

27  MO  •  2(6  R2O3  •  10  SiO2) 
•  30  H2O 

27  MO  =  23.5  FeO  -  2.5  MgO  •  1  MnO 
12  R2O3  =  8  A12O3-  4  Fe2O3 

Thuringite 

Hot 

Springs 

107 

28  MO  •  2(6  R2O3  •  10  SiO2) 
•  32  H2O 

28  MO  =  28  FeO 
12  R2O3=9.5  A12O3  •  2.5  Fe2O3 

» 

Zirmsee 

108 

29MO-2(6Fe203-10Si02) 
•32H2O 

29  M0  =  20  FeO  •  7  MgO  •  2  MnO 

Cron- 
stedtite 

Pfibram 

109 

29MO-2(6Fe203-10Si02) 
•  32  H2O 

„ 

»> 

>» 

110 

30MO-2(6R203-10Si02) 
•  28  H2O 

30  MO  =  23  MgO  •  6  FeO  •  1  MnO 
12R2O3=10.5A12O3-  1.5Fe2O3 

Klementite 

Vielsalm 

111 

30  MO  •  2(6A1203  •  10  SiO2) 
•  32  H2O 

30  MO  =  27.5  FeO  -1  MgO 
•  1  Na2O  •  0.5  MnO 

Daphnite 

Penzance 

112 

30MO-2(6R203-10Si02) 
•  32  H2O 

30  MO  =  21.  5  FeO  •  8.5  MgO 
12  R2O3=11  A12O3  •  1  Fe2O3 

Ortho- 
chlorite 

Diillen 

113 

30MO-2(6Fe203-10Si02) 
•  38  H20 

30  MO  =  23  FeO  •  6  MgO  •  1  MnO 

Cron- 
stedtite 

Pfibram 

114 

34  MO-  2(6  R208  -10810,) 
•32H20 

34  MO  =  22  MgO-  12  FeO 
12  R2O3  =  1  1  A12O3  •  1  Fe2O3 

Ortho- 
chlorite 

Washing- 
ton, D.C. 

115 

36MO-2(6R2O3-10SiO2) 
•28H20 

36  MO  =  15.5  MgO  •  16  FeO  •  0.5  MnO 
12  R2O3=  10.5  A12O3  •  1.5  Fe2O3 

M 

Steeles 
Mount,  N.C. 

THE   ORTHOCHLORITE   GROUP 

or  the  general  formula 

m  MO  •  2  (6  R2O3  •  6  Si02)  •  n  H20. 


395 


Analyst 

Si02 

A120, 

Fe20, 

Cr20, 

FeO   |MnO 

CaO 

MgO 

KaO 

Na20 

H»0 

Total 

Rosam 

Theory 
VI 

16.62 
17.34 

— 

44.32 
43.05 

— 

29.92 
30.27 

0.16 

— 

— 

— 

— 

9.14100.00 
9.18100.00 

or  the  general  formula 

m  MO  -  2  (6  R203  •  10  Si02)  •  n  H20. 


Analyst 

Si02 

A120S 

FezOa 

Cr20, 

FeO    |MnO 

CaO 

MgO 

K.O 

Na,0 

H20 

Total 

Konig 

Theory 
CXXXIV 

32.32 

32.80 

26.10 
26.07 

10.77 
9.80 

— 



- 



17.25 
17.70 





13.56 
13.75 

100.00 
100.12 

?> 

Theory 
CXXXIII 

31.29 
31.35 

21.27 
21.58 

16.67 
14.17 

— 

~ 



z 

16.68 
16.67 

— 



14.09 
14.45 

100.00 

98.22 

Woitschach 

Theory 
V 

27.01 
27.06 

19.52 
19.56 

12.60 
11.71 

- 

29.17 

28.91 

~ 

0.63 
0.38 

1.35 
1.18 

~ 

— 

9.72 
9.73 

100.00 
98.53 

Gintl 

Theory 
CXXXVIII 

29.38 
29.89 

27.47 
30.87 

3.92 

- 

8.81 
9.17 

~ 

~ 

16.64 
17.53 

2.32 
2.41 

0.83 

11.46 
11.60 

100.00 
102.30 

» 

Theory 
CXXXIX 

29.38 
29.90 

27.47 
27.59 

3.92 
3.12 

— 

8.81 
9.17 

~ 

— 

16.64 
17.10 

2.32 
2.33 

0.58 

11.46 
11.51 

100.00 
101.30 

Keyser 

Theory 
VI 

23.98 
23.21 

16.31 
15.59 

12.79 
13.89 

- 

34.53 
34.51 

~ 

0.36 

1.60 
1.26 

0.08 

0.41 

10.79 
10.59 

100.00 
99.97 

Smith 

Theory 
III 

23.98 
23.55 

16.31 
15.63 

12.79 
13.79 

- 

34.53 
34.20 

~ 

z 

1.60 
1.47 

~ 

— 

10.79 
10.57 

100.00 
99.21 

» 

Theory 
VII 

24.01 
23.58 

16.32 
16.85 

12.80 
14.33 

— 

33.85 
33.20 

0.09 

z 

1.60 
1.52 

— 

0.62 
0.46 

10.80 
10.45 

100.00 
100.48 

95 

Theory 
VIII 

24.01 
23.52 

16.32 
16.08 

12.80 

- 

33.85 
32.18 

~ 

z 

1.60 
1.68 

~ 

0.62 

10.80 
10.48 

100.00 

Ludwig 

Theory 
V 

22.76 
22.21 

~ 

36.43 
37.49 

- 

25.96 

25.28 

1.35 
1.20 

— 

5.31 
5.23 

- 

~ 

8.19 

8.27 

100.00 
99.68 

Smith 

Theory 
IX 

23.77 
23.70 

16.17 
16.54 

12.68 
12.13 

- 

33.29 
33.14 

1.41 
1.16 

— 

1.98 
1.85 

0.32  (K. 

O,Na2O) 

10.70 
10.90 

100.00 
99.74 

Gintl 

Theory 

V 

23.25 
22.65 

18.77 

18.92 

7.75 
8.12 

- 

39.06 
38.49 

— 

— 

— 

- 

~ 

11.17 

10.78 

100.00 
98.96 

Steinmann 

Theory 
I 

21.59 
22.45 



34.55 

58.85 

(Fe2O3+FeO) 

25.91 

2.55 
2.89 



5.04 
5.08 

— 

— 

10.37 
10.70 

100.00 
99.97 

Kobell 

Theory 
II 

21.59 
22.45 



34.55 
35.35 

— 

25.91 
27.11 

2,55 

2.89 



5.04 
5.08 

— 

— 

10.37 
10.70 

100.00 
103.58 

Klement 

Theory 

27.04 
27.13 

24.13 

24.70 

5.41 

5.84 

~ 

9.73 
9.72 

1.69 
1.98 

- 

20.73 
20.52 





11.36 
11.35 

100.00 
101.24 

R.v.Zeynek 

Theory 

23.46 
23.62 

23.92 

22.26 

— 

— 

38.70 
38.97 

0.67 
0.98 

0.29 

0.78 
1.09 

0.28 

1.21 
1.10 

11.26 
11.16 

100.00 
99.75 

v.  Giimbel 

Theory 
V    ' 

24.26 
23.56 

22.69 
22.35 

3.23 
4.25 

— 

31.30 
30.43 



0.23 

6.87 
6.75 

O.lOAlk 



11.65 
11.49 

100.00 
99.16 

Janowsky 

Theory 
IV 

20.78 
21.30 



33.26 
32.34 

— 

28.70 
29.23 

1.23 
1.25 



4.15 
4.51 



__ 

11.88 
11.90 

100.00 
100.53 

Clarke  and 
Schneider 

Theory 
CL 

24.99 
25.40 

23.36 

22.80 

3.33 

2.86 

~ 

17.99 

17.77 

0.25 

- 

18.33 
19.09 

- 

- 

12.00 
12.21 

100.00 
100.38 

Genth 

Theory 
CLXI 

24.78 
24.90 

22.12 
21.77 

4.96 
4.60 

___ 

23.79 
24.21 

1.14 
1.15 

- 

12.81 

12.78 

- 

~ 

10.40 
10.59 

100.00 
100.00 

396 


THE   ORTHOCHLORITE   GROUP 


1 

Source 

116 

36  MO  •  2  (6  R2O3  • 

10  SiO2) 

36  MO  =  22  MgO  •  14  FeO 

Orthochlorite 

Lude 

•  32  H2O 

12  R2O3=11.5Al2O3-0.5Fe2O3 

,, 

117 

36  MO  •  2  (6  R2O3  • 

10  SiO2) 

36  MO  =  22  MgO  •  14  FeO 

n 

•  32  H2O 

12  RaOa  =  11.5  A12O3  •  0.5  Fe2O3 

118 

37.MO-2(6R2<V 

10  SiO2) 

37  MO  =  25  MgO  •  12  FeO 

M 

Chester, 

•  34  H2O 

12  R2O3  =  11.5  A12O3  •  0.5  Fe2O3 

Mass. 

119 

38  MO  •  2  (6  A1203 

•  10  SiO2) 

38  MO  =  28  MgO  -10  FeO 

w 

» 

•32H20 

L.  Orthochlorites  of  the  type 
Si  •  R  •  R  •  Si  =  6  R203  •  12  Si02 

Source 

120 

18MO-2(6R2O3-  12SiO2) 
•  28  H2O 

18  MO  =  15  MgO  •  2.5  K2O  •  0.5  Na2O 
1  2  R2O3  =  9  A12O3  •  3  Fe2O8 

Ortho- 
chlorite 

Culsagee  Mine, 

N.C. 

121 

24  MO  •  2(6R2O3  •  12  SiO2) 
•26H2O 

24  MO  =  18.5  FeO  •  5  MnO  •  0.5  CaO 
12  R2O3=8.5  A12O3  -  3.5  Fe2O3 

Strigo- 
vite 

Striegau 

122 

25  MO  •  2  (6  R2O3  •  12SiO2) 
•  24  H2O 

25  MO  =  10  FeO  •  10.5  MgO  •  3.5  CaO 
•1  Na2O;  12  R2O3=8  A12O3  •  4  Fe2O3 

Chloro- 
pite 

Weidesgriin 

123 

25MO-2(6R2O3-12Si02) 
•  30  H2O 

25  MO  =  22  MgO  -  2.5  FeO  •  0.5  CaO 
12R203=7Al203-5Fe2O3 

Deles- 
site 

La  Greve 
bei  Mielin 

124 

26MO-2(6R2O3-12Si02) 
•40H20 

26  MO  =  22  FeO  •  2  MgO  -  2  CaO 
12  R2O3=11.5  A12O3  •  0.5  Fe203 

Ortho- 
chlorite 

Striegau 

125 

28MO-2(6R203  •  12  SiO2) 
•  22  H20 

28  MO  =  6.5  MgO  •  20  FeO  •  1  K2O 
•0.5  MnO;  12R2O3  =  9  Al2O3-3Fe2O3 

» 

Waldsassen 

126 

29MO-2(6R203-12Si03) 
•34H20 

29  MO  =  18.5  MgO  •  10  FeO  •  0.5  CaO 
12  R2O3  =  9.6  A12O3  •  2.5  Fe2O3 

Delassite 

Planitz  bei 
Zwickau 

127 

30MO-2(6R203-12Si02) 
•28H20 

30  MO  =  17.5  FeO  -  11.5MgO-0.5  K2O 
•0.5  Na2O;  12R2O3=7.5  Al2O3-4.5Fe2O3 

Chloro- 
pite 

Schwarzen- 
bach 

128 

30MO-2(6R203-12Si02) 
•  30  H2O 

30MO  =  9  FeO-18.5  MgO-1  CaO-1  Na2O 
•05  K2O;  12  R2O3  =  7  A12O3  •  5  FeaO3 

H 

Lippertsgriin 

129 

30  MO  •  2  (6  A12O3  •  12  SiO2) 
•32H20 

30  MO  =  20  FeO  •  10  MgO 

Ortho- 
chlorite 

Taszopatak 

130 

35  MO  •  2  (6  A12O3  •  12  SiO2) 
•  24  H2O 

35  MO  =33.5  FeO  •  1.5  MgO 

Aphro- 
siderite 

Weilburg 

131 

36MO-2(6R2O3-  12SiO2) 
•  30  H2O 

36  MO  =  29.5  FeO  •  6.5  MgO 
12  R203=10  A1203  •  2  Fe203 

» 

Striegau 

132 

36MO-2(6Al203-12Si02) 
•  40  H20 

36  MO  =  30  FeO  -6  MgO 

Chamo- 
site 

Windgallen 

133 

38MO-2(6R203-12SiO2) 
•  32  H20 

38  MO  =  16  MgO  -22  FeO 
1  2  R2O3  =  1  1  A12O3  •  1  Fe2O3 

Ortho- 
chlorite 

Mutters- 
hausen 

134 

38MO-2(6R203-12SiO2) 
•  32  H20 

38MO  =  16MgO-22FeO 
12R203  =  llAl203-lFe203 

» 

Balduinstein 

135 

38MO-2(6R203-12Si02) 
•  34  H20 

38  MO  =  34  MgO  -4  FeO 
12R203=llAL03-lFe2O3 

» 

Unionville, 
Pa. 

136 

38MO-2(6Ro03-12Si02) 
•  34  H26 

38  MO  =  34  MgO  -4  FeO 
12R203  =  llAl203-lFe2O3 

» 

>» 

137 

38MO-2(6R203-12Si02) 
•  34  H20 

38  MO  =  31  FeO  •  6.5  MgO  •  0.5  CaO 
12  R2O3=  10  A12O3  •  2  Fe2O3 

Meta- 
chlorite 

Bvichenberge 
b.  Elbingerode 

THE   ORTHOCHLORITE   GROUP 


397 


Analyst 

Si02 

A1203 

Fe208  1  Cr2O, 

FeO 

MnO 

CaO 

MgO 

K20 

NaaO 

H2O 

Total 

Heddle 

Theory 
LXXIII 

24.40 
23.92 

23.86 
22.98 

1.62 
1.11 

~ 

20.50 
19.54 

0.28 

2.45 

17.90 
17.26 

~ 

11.72 
11.78 

100.00 
99.32 

» 

Theory 
LXXIV 

24.40 
24.66 

23.86 
23.19 

1.62 
0.64 

— 

20.50 

20.58 

0.29 

0.40 

17.90 
17.79 

— 

— 

11.72 
12.12 

100.00 
99.67 

Obermayer 

Theory 
CXXIII 

24.35 
23.84 

23.80 
25.22 

1.62 
2.81 

— 

17.53 
17.06 



— 

20.29 
19.83 





12.41 
11.90 

100.00 
100.66 

Pasani 

Theory 
CXXI 

24.79 
24.00 

25.29 
25.90 

~ 

z 

14.88 
14.80 

— 

— 

23.14 

22.70 

~ 

11.90 
11.90 

100.00 
99.30 

or  the  general  formula 

m  MO  •  2  (6  R203  •  12  Si02)  •  n  H20. 


Analyst 

SiO,  |  AljOs  |  Fe208  |  Cr2O, 

FeO 

MnO 

CaO 

MgO 

K20 

Na,0  |   H20   |    Total  , 

Chatard 

Theory 

34.32 

21.81 

11.41 

— 



— 

— 

14.26 

5.58 

0.74 

11.98 

100.00 

CLVII 

34.22 

21.53 

12.41 

— 

.12(Ni.Co)o 

— 

14.46 

5.70 

0.51 

11.85 

100.80 

Websky 

Theory 

28.53 

17.17 

11.09 



26.39 

6.99 

0.55 



— 

— 

9.28 

100.00 

I 

28.43 

16.60 

11.43 

— 

26.21 

7.25 

0.37 

0.36 

— 

— 

9.31 

99.96 

Loretz 

Theory 

30.46 

17.26 

13.54 



15.24 

— 

4.16 

8.89 



1.31 

9.14 

100.00 

II 

30.56 

16.57 

13.02 

— 

15.51 

— 

4.14 

8.97 

0.36 

1.18 

1  9.08 

99.39 

(Delesse 

Theory 

31.43 

15.58 

17.46 



3.93 

— 

0.60 

19.21 





11.79 

100.00 

I 

31.07 

15.47 

17.54 

— 

4.07 

— 

0.46 

19.14 

— 

— 

11.55 

99.30 

Traube 

Theory 

27.75 

22.61 

— 

1.54 

30.52 

— 

2.15 

1.54 

— 

— 

13.89 

100.00 

X 

27.12 

22.40 

— 

2.13 

30.19 

— 

2.23 

1.54 

— 

— 

13.45 

99.06 

»v.  Giimbel 

Theory 

27.99 

19.41 

9.33 



27.99 

0.69 



5.05 

1.83 



7.71 

100.00 

IV 

27.50 

18.15 

10.80 

— 

28.02 

0.60 

— 

5.13 

1.66 

0.44 

7.50 

99.80 

Delesse 

Theory 

29.33 

19.74 

8.14 

— 

14.67 

— 

0.57 

15.07 

— 

— 

12.48 

100.00 

III 

29.45 

18.25 

8.17 

— 

15.12 

— 

0.45 

15.32 

— 

— 

12.57 

99.33 

1         Loretz 

Theory 

27.55 

14.63 

13.77 

— 

24.12 

— 

— 

8.80 

0.90 

0.59 

9.64 

100-00 

I 

27.10 

14.64 

14.80 

— 

23.85 

— 

— 

8.78 

0.52 

0.56 

9.69 

99.94 

„ 

Theory 

28.44 

14.10 

15.80 



12.80 



1.10 

14.64 

0.92 

1.22 

10.98 

100.00 

III 

29.10 

14.31 

14.87 

— 

13.27 

— 

1.00 

15.08 

0.60 

1.09 

10.77 

100.09 

K.  v.  Hauer 

Theory 

28.35 

24.10 





28.35 





7.87 

_^_ 



11.33 

100.00 

XVII 

28.02 

23.84 

— 

— 

28.60 

— 

— 

8.09 

— 

— 

11.45 

100.00 

Sandberger 

Theory 

25.86 

21.98 





43.32 

— 



1.08 





7.76 

100.00 

I 

26.45 

21.25 

— 

— 

44.24 

— 

— 

1.06 

— 

— 

7.74 

100.74 

Rammelsberg 

Theory 

25.24 

17.88 

5.61 



37.24 

— 



4.56 





9.47 

100.00 

IV 

24.78 

18.69 

6.45 

— 

36.17 

Trace 

— 

4.52 

— 

— 

9.09 

99.70 

C.  Schmidt 

Theory 

24.90 

21.16 





37.35 





4.14 



— 

12.45 

100.00 

II 

25.23 

19.97 

— 

— 

37.51 

— 

— 

4.39 

— 

— 

12.90 

100.00 

Erlenmeyer 

Theory 

26.07 

20.32 

2.90 



28.69 

— 

— 

11.59 

— 

— 

10.43 

100.00 

VI 

25.72 

20.69 

4.01 

— 

27.79 

— 

— 

11.70 

— 

— 

10.05 

99.96 

ff 

Theory 

26.07 

20.32 

2.90 

— 

28.69 

— 

— 

11.59 

— 

— 

10.43 

100.00 

VII 

25.99 

— 

4.13 

— 

27.60 

— 

— 

11.93 

— 

— 

10.13 

— 

Chatard 

Theory 

28.68 

22.35 

3.13 



5.75 





27.90 





12.19 

100.00 

cxxxv 

29.43 

22.0 

I  A" 

— 

5.64 

— 

— 

28.46 

— 

— 

12.40 

99.42 

» 

Theory 

28.68 

22.35 

3.13 



5.75 





27.90 





12.19 

100.00 

CXXXVI 

29.59 

22.1 

1.33 

— 

5.77 

— 

— 

28.54 

— 

— 

12.40 

99.81 

Zeynek 

Theory 

24.36 

17.2 

5.4 



37.75 



0.47 

4.40 





10.36 

100.00 

II 

24.2S 

17.8 

4.6-J 

— 

37.85 

— 

0.57 

4.26 

0.09 

0.30 

10.19 

100.04 

398 


THE   ORTHOCHLORITE   GROUP 


1 

Source 

138 

39  MO  •  2  (6  A12O3  •  12  SiO2) 
•30H2O 

39  MO  =  25  FeO-  14MgO 

Ortho- 
chlorite 

Grabener 
Wiesen 

139 

39MO-2(6R2O3-12SiO2) 
•  34  H2O 

39  MO  =  25  MgO-  12  FeO-  1  K2O 
•1  Na2O;  12  R2O3=  10.5Al2O3-1.5Fe2O3 

» 

Fuschertal 

140 

39  MO  •  2  (6  R2O3  •  12  SiO2) 
•  36  H2O 

39  MO  -  19  MgO  •  20  FeO 
12  R2O3=  10.5  A12O3  •  1.5  Fe2O3 

H 

Zillerthal 

141 

39  MO  •  2  (6  Fe2O3  •  12SiO2) 
•  36  H2O 

39  MO  =  31.  5  FeO  -6.5  MgO-  1  MnO 

Cronsted 
tite 

Pfibram 

142 

40MO-2(6R203-12Si02) 
•  36  H20 

40  MO  =  19  MgO  -21  FeO 
1  2  R2O3  =  1  1  A12O3  •  1  Fe2O3 

Ortho- 
chlorite 

Zillertal 

143 

41MO-2(6R2O3-12SiO2) 
•  40  H20 

41  MO  =  37  MgO  -4  FeO 
12  R2O3=  11.5  A12O3  •  0.5  Fe2O3 

» 

Culsagee  Mine, 
N.C. 

144 

41MO-2(6R2O3-  12SiO2) 
•  40  H2O 

41  MO  =  37  MgO  -4  FeO 
12  R2O3  =  11.5  A12O3  •  0.5  Fe2O3 

n 

M 

145 

41MO-2(6R2O3-12SiO2) 
•  40  H2O 

41  MO  =  37  MgO  -4  FeO 
12  R2O3=  11.5  A12O3  •  0.5  Fe2O3 

» 

" 

146 

42MO-2(6Al203-12Si02) 
•  36  H20 

42  MO  =  21  FeO  •  19  MgO  •  1  K2O 
•0.5  MnO  •  0.5  CaO 

f> 

Ben  Derag 

147 

42MO-2(6R203-12Si02) 
•  38  H20 

42  MO  =  26  MgO  -16  FeO 
12  R2O8  =  11.5  A12O3  •  0.5  Fe2O3 

H 

Aacherkoppe 

148 

43  MO  •  2  (6  R2O3  •  12SiO2) 
•34H20 

43  MO  =  25  MgO  -18  FeO 
12  R2O3=  11.5  A12O3  •  0.5  Fe2O3 

H 

St.  Gotthard 

149 

43MO-2(6R2O3-  12SiO2) 
•  34  H2O 

43  MO  =  32  MgO  •  10.5  FeO  •  0.5  MnO 
12R2O3  =  llAl203-lFe203 

»» 

Portsoy 

150 

43MO-2(6Al2O3-12SiO2) 
•  36  H2O 

43MO  =  32MgO-llFeO 

» 

Zillertal 

151 

43MO-2(6A12O3-12  SiO2) 
•  36  H2O 

»               »               >» 

M 

»> 

152 

43  MO  •  2  (6  R2O3  •  12SiO2) 
•38H2O 

43  MO  =  22  MgO  •  20  FeO  •  1  CaO 
12  R2O3=  1  1.5  A12O3  •  0.5  Fe2O3 

n 

Massa- 
schlucht 

153 

43  MO  •  2  (6  R2O3  •  12  SiO2) 
•  40  H2O 

43  MO  =  19.5  MgO  •  22  FeO  •  1  CaO 
•0.5MnO;12R2O3  =  11.5Al2O3-0.5Fe2O3 

M 

Girdleness 

154 

44  MO  •  2  (6  R2O3  •  12  SiO2) 
•  30  H2O 

44  MO  =  22  MgO  •  22  FeO 
12R2O3  =  11.5Al2O3-0.5Fe2O3 

» 

ZiUertal 

155 

44MO-2(6Al203-12Si02) 
•34H20 

44  MO  =  40  MgO  -4  FeO 

H 

Grochau 

156 

46MO-2(6Al2O3-12SiO2) 
•24H20  ' 

46  MO  =  20.5  MgO  •  25.5  FeO 

M 

Guistberg 

157 

48  MO  •  2  (6  R2O3  •  12  SiO2) 
•  38  H2O 

48  MO  =  33  MgO  •  14  FeO  •  0.5  MnO 
•O.SCaO;  12R2O3=11.5  Al2O3-0.5Fe2O3 

n 

Fethaland 

158 

51MO-2(6A12O3-  12SiO2) 
•32H2O 

51MO  =  31MgO-16FeO-2CaO-lK2O 
•  0.5  MnO  •  0.5  Na2O 

» 

Craig  an 
Lochan 

M.  Orthochlorites  of  the  type 
Si  •  R  •  SAi  •  R  •  Si  =  6  R203  •  16  Si02 


Source 

159 
160 

32  MO- 
41  MO  • 

2  (6  R20a 
36H2O 

2(6R2Oa 
52H2O 

•  16  Si02) 
•16Si02) 

32  MO  =  30  MgO  -2  FeO 
12  R2O3  =  6.5  A12O3  •  1  Fe2O3-4.5Cr2O3 

41  MO  =  29.5  MgO  •  10  FeO  •  1.5  CaO 
12  RaO,=  11.5  A12O3  -  0.5  Fe2O3 

Ortho- 
chlorite 

Delessite 

Norrbotten 
Dumbuek 

THE   ORTHOCHLORITE   GROUP 


399 


Analyst 

Si02 

A1203 

Fe20, 

Cr203 

FeO 

MnO 

CaO  |  MgO 

K,0 

NajO 

H,o 

Total 

K.  v. 

Theory 

25.82 

21.93 





32.26 





10.03 





9.96 

100.00 

Hauer 

XVIII 

26.08 

20.27 

— 

— 

32.91 

— 

— 

10.00 

— 

— 

10.06 

99.32 

Vuylsteke 

Theory 

26.75 

19.89 

4.46 



16.06 

— 

— 

18.57 

1.74 

1.15 

11.38 

100.00 

XIX 

27.03 

20.07 

4.72 

— 

16.47        — 

— 

18.90 

1.22 

0.72 

11.78 

100.91 

Klement 

Theory 

25.72 

19.13 

4.29 

. 

25.72 



— 

13.58 

— 

— 

11.56 

100.00 

XXIX 

25.84 

19.58 

4.42 

— 

25.99 

— 

— 

13.57 

— 

— 

11.34 

100.74 

D  amour 

Theory 

21.89 



29.06 



34.33 

1.07 

— 

3.93 

— 

— 

9.81 

100.00 

III 

21.39 

29.08 

— 

33.52 

1.01 

— 

4.02 

— 

— 

9.76 

98.78 

Klement 

Theory 

25.52 

19.89 

2.84 

— 

26.80 

— 

— 

13.46 

— 

— 

11.49 

100.00 

XXX 

25.84 

19.58 

2.13 

— 

28.05 

— 

— 

13.57 

— 

— 

11.34 

100.51 

Genth 

Theory 

27.79 

22.64 

1.55 



5.56 

— 

— 

28.56 

— 

— 

13.90 

100.00 

CLIII 

27.56 

22.75 

2.56 

— 

5.43 

— 

— 

28.47 

0.30(Mn,Ni,Co)0 

13.80 

100.87 

Chatard 

Theory 

27.79 

22.64 

1.55 



5.56 

__ 

, 

28.56 





13.90 

100.00 

CLIV 

27.28 

22.11 

2.50 

— 

5.43 

— 

— 

28.38 

0.41  (Mn,  Ni,  Co)O 

14.50 

100.57 

» 

Theory 

27.79 

22.64 

1.55 



5.56 





28.56 

— 

— 

13.90 

100.00 

CLV 

27.17 

22.35 

2.71 

— 

5.43 

— 

— 

27.73 

0.26  (Mn,  Ni,  Co)O 

14.36 

100.00 

Heddle 

Theory 

25.11 

21.34 

— 



26.35 

0.62 

0.40 

13.25 

1.63 

— 

11.30 

100.00 

LXXI 

24.72 

21.57 

0.62 

— 

26.16 

0.47 

0.45 

12.86 

1.73 

0.05 

10.89 

99.52 

Jacobs 

Theory 

25.86 

21.07 

1.43 



20.68 





18.68 

— 

— 

12.28 

100.00 

VIII 

25.53 

20.49 

1.68 

0.08 

20.85 

0.15TiO2 

0.06 

18.60 

0.07 

0.09 

12.26 

99.86 

Rammels- 

Theory 

25.71 

20.95 

1.43 

P205 

23.14 

— 

— 

17.85 

— 

— 

10.92 

100.00 

berg 

XXXIV 

25.12 

22.26 

1.09 

23.11 

— 

— 

17.41 

— 

— 

10.70 

99.69 

Heddle 

Theory 

26.59 

20.72 

2.95 

— 

13.96 

0.83 

— 

23.64 

— 

— 

11.31 

100.00 

LXXVI 

26.71 

20.42 

3.47 

— 

13.99 

0.73 

— 

23.90 

— 

— 

11.17 

100.39 

Kobell 

Theory 

26.74 

22.72 

— 

— 

14.71 

— 



23.77 

— 

— 

12.06 

100.00 

XXVI 

26.51 

21.81 

— 

— 

15.00 

— 

22.83 

— 

— 

12.00 

98.15 

n 

Theory 

26.74 

22.72 

— 

— 

14.71 

— 



23.77 

— 

— 

12.06 

100.00 

XXVII 

27.32 

20.69 

— 

15.23 

0.47 

— 

24.89 

— 

— 

12.00 

100.60 

Fellen- 

Theory 

25.03 

20.39 

1.39 

^_ 

25.03 



0.97 

15.29 





11.90 

100.00 

berg 

XXXV 

24.85 

20.70 

1.00 

— 

25.00 

— 

0.60 

15.31 

0.45  Ti02 

12.05 

99.96 

Heddle 

Theory 

24.53 

19.97 

1.36 



27.04 

0.60 

0.95 

13.28 

__ 



12.27 

100.00 

LXXVII 

24.77 

20.16 

1.38 

— 

27.38 

0.61 

0.90 

13.34 

— 

— 

12.05 

100.59 

Egger 

Theory 

25.28 

20.59 

1.42 



27.80 

— 



15.45 

— 

— 

9.48 

100.00 

XXVIII 

26.02 

20.16 

1.07 

— 

28.08 

— 

0.44 

15.50 

— 

— 

9.65 

100.92 

Bock 

Theory 

27.88 

23.70 





5.58 

— 

— 

30.99 

— 

— 

11.85 

100.00 

IX 

28.20 

24.56 

— 

— 

5.27 

— 

— 

30.94 

— 

— 

12.15 

101.12 

Igelstrom 

Theory 

25.03 

21.28 





31.92 

— 

— 

14.25 

— 

— 

7.52 

100.00 

LXXXIII 

25.00 

20.60 

— 

— 

32.00 

— 

— 

14.30 

— 

— 

7.60 

99.50 

Heddle 

Theory 

24.96 

20.33 

1.39 

— 

17.48 

0.61 

0.49 

22.88 

— 

— 

11.86 

100.00 

LXX 

24.30 

20.86 

3.57 

— 

16.72 

0.55 

0.50 

22.20 

— 

— 

11.55 

100.25 

Theory 

24.39 

20.73 



__ 

19.51 

0.59 

1.96 

21.00 

1.59 

0.52 

9.77 

100.00 

LXXII 

24.29 

21.15 

0.10 

— 

18.74 

0.80 

1.66 

21.03 

1.29 

0.56 

10.08 

99.70 

or  the  general  formula 

m  MO  •  2  (6  R203  •  16  Si02)  •  n  H20. 


Analyst 

SiOa 

AljO, 

FesO, 

CraOs 

FeO 

MnO 

CaO 

MgO 

K,o 

Na,0 

H,O 

Total 

Sanderson 

Theory 
LXXXVII 

35.42 
34.49 

12.23 
12.40 

2.95 
3.14 

12.64 
13.46 

2.66 
3.28 

— 

z 

22.14 
21.83 

__ 

— 

11.96 
11.85 

100.00 
100.45 

Heddle 

Theory 
VII 

31.52 
32.01 

19.25 

18.87 

1.31 
1.18 

— 

11.82 
12.09 

Trace 

1.37 
1.39 

19.36 
19.64 

- 

- 

15.37 
15.46 

100.00 
100.64 

400 


THE   ORTHOCHLORITE   GROUP 


Source 

161 

48  MO  •  2  (6  A12O3  •  16  SiO2) 

48  MO  =  43  MgO  -5  FeO 

Ortho- 

Brosso 

•  32  H2O 

chlorite 

162 

48MO-2(6RoO3-16SiO2) 

48  MO  =  48  MgO 

»> 

Westchester, 

•  40  H26 

12R2O3=10Al2O3-1.5Fe2O3-0.5Cr2O3 

Pa. 

163 

48MO-2(6R2O3-16SiO2) 

48  MO  =  48  MgO 

» 

t 

•40H20 

12  R2O3=  10  A12O3-1.5  Fe2O3-0.5  Cr2O3 

164 

49MO-2(6R2O3-16SiO2) 

49  MO  =  47  MgO  -2  FeO 

»» 

Zoutpansberge 

•46H20 

12  R2O3=  11.5  A12O3  •  0.5  Fe2O3 

165 

51MO-2(6R2O3-16Si02) 
-40H20 

51  MO  =  26  MgO  •  21  FeO  •  4  MnO 
12  R2O3=9.5  A12O3  •  2.5  Fe2O3 

" 

Dannemora 

166 

51MO-2(6R2O3-16SiO2) 

51  M0  =  26  MgO  •  21  FeO  •  4  MnO 

J? 

» 

•40H20 

12  R2O3=9.5  A12O3  •  2.5  Fe2O3 

167 

52  MO  •  2  (6  A12O3  •  16  SiO2) 

52  MO  =  23  MgO  •  29  FeO 

» 

St.  Christophe 

•  44  H2O 

168 

53  MO  •  2  (6  A12O3  •  16  SiO2) 

53  MO  =  46  MgO  -7  FeO 

>» 

Blair  Athol 

•  46  H2O 

169 

53MO-2(6R203-16Si02) 

53  MO=52.5  MgO  •  0.5  FeO 

>? 

Achmatowsk 

-  46  H2O 

12  R2O3=  11  A12O3  •  1  Fe2O3 

170 

55  MO  •  2  (6  R2O3  •  16  SiO2) 

55  MO  =  51  MgO  •  2  FeO  •  2  Na2O 

5> 

Westchester, 

•50H20 

12  R2O3  =  11  Al2O3-0.5Fe2O3-0.5Cr2O3 

Pa 

171 

55  MO  •  2  (6  R2O3  •  16  SiO2) 

55  MO  =52  MgO  •  2  FeO  •  1  CaO 

>» 

>» 

•  40  H20 

12  R2O3  =  11  Al2O3-0.5Fe2O3-0.5  Cr2O3 

172 

55MO-2(6R2O3-16SiO2) 

55  MO  =  53  MgO  -2  FeO 

»f 

)f 

•  48  H2O 

12  R2O3=9  A12O3  •  2  Fe2O3  •  1  Cr2O3 

173 

56  MO  •  2  (6  R2O3  •  16  SiO2) 

56  MO  =  53  MgO  -3  FeO 

?> 

Itkul  Sea 

•  42  H20 

12  R203=  10  A1203  •  2  Cr203 

174 

56  MO  •  2  (6  A12O3  •  16  SiO2) 

56  MO  =  54  MgO  -2  FeO 

ff 

Schischimsker 

•44H20 

Berge 

175 

56MO-2(6Al2O3-16Si02) 

56  MO  =54  MgO  -2  FeO 

» 

»5 

•44H20 

176 

56  MO  •  2  (6  A12O3  •  16  SiO2) 

»               j>             » 

» 

)} 

•44H20 

177 

58  MO  •  2  (6  A12O3  •  16  SiO2) 

58  MO  =  29  MgO-29  FeO 

>» 

Glacier  d'Ar- 

•  40  H2O 

gentieres 

178 

58  MO  •  2  (6  R2O3  •  16  SiO2) 

58  MO  =  58  MgO 

n 

FluB  Iremel 

•  42  H2O 

12  R2O3  =  1  1  A12O3  •  1  Fe2O3 

179 

61  MO  •  2  (6  A12O3  •  16  SiO2) 

61  MO  =  54  MgO  •  3.5  FeO  •  2  CaO 

tt 

Texas,  Pa. 

•  52  H2O 

•1.5K20 

N.  Orthochlorites  of  the  type 
Si  •  R  •  Si  •  R  •  Si  =  6  R2O3  •  18  Si02 


Source 

180 
181 

182 

18MO- 
23  MO- 
36  MO- 

2  (6  R203  • 
42H2O 

2  (6  R203  • 
34H2O 

2  (6  A12O3  • 
26H2O 

18  SiO2) 
18  SiO2) 
18  SiO2) 

18  MO  =  10.5  MgO  •  4.5  CaO  •  3  FeO 
12R203  =  7Fe203-5Al203 

23MO  =  21,5FeO-1.5Na20 
12  R2O3=9  Fe2O3  •  3  A12O3 

36  MO  =  20  MgO  -16  FeO 

Hullite 

Melano- 
lite 

Epi- 
phanite 

Carnmoney 
Hill 
Milk-Row 
Quarry,  Mass. 
Wermland 

THE   ORTHOCHLORITE   GROUP 


401 


Analyst 

Si02 

Al,o, 

Fe203 

Cr20» 

FeO 

MnO 

CaO 

MgO 

K20 

Na2O 

H»0 

Total 

Damour 

Theory 

33.10 

21.10 

— 



6.21 





29.64 



_ 

9.95 

100.00 

LVI 

33.67 

20.37 

— 

— 

6.37 

— 

— 

29.49 

— 

— 

10.10 

100.00 

Graw 

Theory 

32.56 

17.30 

4.07 

1.29 







32.56 





12.22 

100.00 

CXXVIII 

nri 

31.34 

17.47 

3.85 

1.69 

— 

— 

— 

33.44 

— 

— 

12.60 

100.39 

» 

Theory 
CXXIX 

32.56 
31.78 

— 

22.71 

— 







32.56 
33.64 

__ 



12.22 
12.60 

100.00 
100.73 

Yvan  Riesen 

Theory 

31.86 

19.47 

1.33 

— 

2.39 





31.21 

_ 



13.74 

100.00 

cxv 

32.38 

18.79 

0.80 

— 

2.39 

— 

— 

31.64 

— 

— 

14.15 

100.15 

Erdmann 

Theory 

28.05 

14.15 

5.84 

— 

22.09 

4.15 



15.19 





10.53 

100.00 

LXXX 

27.83 

14.23 

5.34 

— 

22.53 

3.21 

— 

15.42 

0.36 

0.27 

10.19 

99.38 

Jf 

Theory 

28.05 

14.15 

5.84 

— 

22.09 

4.15 



15.19 





10.53 

100.00 

LXXXI 

27.89 

14.30 

5.96 

— 

21.21 

5.43 

0.43 

14.42 

0.17 

0.23 

10.30 

100.34 

Marignac 

Theory 

27.65 

17.63 

— 

— 

30.07 





13.25 





11.40 

100.00 

LIX 

26.88 

17.52 

— 

— 

29.76 

— 

— 

13.84 

— 

— 

11.33 

99.33 

Heddle 

Theory 

30.40 

19.38 

— 

— 

7.98 





29.13 





13.11 

100.00 

LXVI 

30.30 

19.40 

— 

— 

8.23 

0.37 

— 

29.10 

— 

— 

13.07 

100.47 

Ortraann 

Theory 

31.15 

18.19 

2.59 

— 

0.58 

,  



34.05 





13.44 

100.00 

XCIV 

31.31 

18.34 

2.10 

— 

0.77 

— 

— 

34.25 

0.06 

0.17 

13.33 

100.33 

Schlaepfer 

Theory 

29.96 

17.52 

1.25 

1.18 

2.25 





31.85 



1.94 

14.05 

100.00 

CXXXII 

30.11 

18.31 

1.16 

1.55 

2.11 

0.31  Li,0 

— 

31.89 

0.37 

1.99 

14.14 

101.94 

Neminar 

Theory 

30.98 

18.11 

1.29 

1.23 

2.32 



0.90 

33.56 





11.61 

100.00 

cxxx 

31.08 

18.85 

1.55 

1.09 

2.33 

— 

0.81 

33.50 

— 

— 

11.53 

100.74 

Clarke  and 

Theory 

29.83 

14.26 

4.97 

2.36 

2.24 





32.93 





13.41 

100.00 

Schneider 

CXXXI 

29.87 

14.48 

5.52 

1.56 

1.93 

— 

— 

33.06 

0.17NIO 

— 

13.60 

100.19 

Hermann 

Theory 

30.31 

16.09 



4.81 

3.40 





33.45 





11.94 

100.00 

CXII 

30.58 

15.94 

— 

4.99 

3.32 

— 

— 

33.45 

— 

— 

12.05 

100.33 

Herzog  N.v 

Theory 

30.77 

19.62 



— 

2.31 

__ 



34.61 





12.69 

100.00 

Leuchtenberg 

XCVIII 

30.60 

19.63 

— 

— 

2.02 

— 

— 

34.41 

— 

— 

12.76 

99.42 

,, 

Theory 

30.77 

19.62 

— 

— 

2.31 





34.61 





12.69 

100.00 

XCIX 

30.33 

19.85 

— 

— 

2.43 

— 

0.11 

34.64 

— 

— 

12.73 

100.09 

Lagorio 

Theory 

30.77 

19.62 

— 

— 

2.31 





34.61 





12.69 

100.00 

C 

30.61 

19.52 

0.30 

— 

2.53 

— 

— 

34.20 

— 

— 

12.53 

99.69 

Brun 

Theory 

27.00 

17.21 

— 

— 

29.36 





16.31 





10.13 

100.00 

XLIX 

26.60 

18.02 

— 

— 

29.67 

— 

— 

15.85 

— 

— 

9.98 

100.12 

Hermann 

Theory 

30.58 

17.87 

2.55 









36.96 





12.04 

100.00 

CX 

30.80 

17.27 

1.37 

— 

— 

— 

— 

37.08 

— 

— 

12.30 

98.82 

Pearse 

Theory 

28.47 

18.15 



— 

3.73 

1.66 



32.02 

2-09 

— 

13.88 

100.00 

CXL 

28.62 

18.37 

— 

0.37NiO 

3.73 

1.45 

— 

32.13 

1.97 

— 

14.02 

100.00 

or  the  general  formula 

m  MO  •  2  (6  R203  •  18  Si02)  •  n  H20. 


Analyst 

Sio, 

A120, 

Fe2O, 

Cr2O, 

FeO 

MnO 

CaO 

MgO 

K,0 

NatO 

H»O 

Total 

Hardmann 

Theory 

39.75 
39.44 

9.39 
10.35 

20.61 
20.72 

— 

3.98 
3.70 

Trace 

4.64 
4.48 

7.73 

7.47 

- 

— 

13.90 
13.62 

100.00 
99.78 

Wurtz 

Theory 
II 

35.07 
35.24 

4.97 
4.48 

23.38 
23.13 

~ 

25.14 
25.09 

— 

~ 

— 

— 

1.51 

1.85 

9.93 
10.21 

100.00 
100.00 

Igelstrom 

Theory 

37.22 
37.10 

21.09 
21.13 

~ 

— 

19.85 
20.00 

Trace 

— 

13.78 
14.03 

— 

— 

8.06 
7.83 

100.00 
100.09 

2    D 


402 


THE   ORTHOCHLORITE   GROUP 


Source 

183 

44MO-2(6R203-18Si02) 
•  42  H20 

44  MO  =  44  FeO 
1  2  R2O3  =  10  A12O3  -  2  Fe2O3 

Chamo- 
site 

Schmiedefeld 

184 

48MO-2(6R2O3-  18SiO2) 
•  48  H20 

48  MO  =  30  MgO  •  17  FeO  •  1  MnO 
12R203  =  10Al203-2Fe203 

Ortho- 
chlorite 

Cape  Wrath 

185 

48MO-2(6R2O3-  18SiO2) 
•  60  H2O 

48  MO  =  34.5  MgO  -11.5  FeO  •  2  CaO 
12  RaO8=  11.5  A12O3  •  0.5  Fe2O3 

Deles- 
site 

Bowling  Quarry, 
Dumbarton 

186 

49  MO  •  2  (6  R2O3  •  18SiO2) 
-  56  H20 

49  M0  =  32.5  MgO  -  15  FeO  •  1.5  CaO 
12  R203  =  10.5  A1203  •  1.5  Fe203 

" 

Long  Craig, 
Dumbarton 

187 

49  MO  •  2  (6  R2O3  •  18SiO2) 
•  44  H20 

49  MO  =  48  MgO  -1  FeO 
12  R2O3=  11.5  A12O3  •  0.5  Fe2O3 

Ortho- 
chlorite 

Ckyn 

188 

52MO-2(6R203-18Si02) 
•  52  H20 

52  MO  =  50  MgO  •  1  CaO  •  1  FeO 
1  2  R2O3  =  1  1  A12O3  •  1  Fe2O3 

»» 

Markich 

189 

54  MO  •  2  (6  R2O3  •  18SiO2) 
•30H20 

54  MO  =  53  MgO  -1  CaO 
12R2O3  =  10.5A12O3-  1.5Fe2O3 

H 

Schischimsker 
Berge 

190 

54  MO  •  2  (6  R2O3  •  18SiO2) 
•  30  H2O 

54  MO  =  53  MgO-  1  CaO 
12  R2O3=  10.5  A12O3  •  1.5  Fe2O3 

" 

» 

191 

57MO-2(6A12O3-  18SiO2) 
•  46H2O 

57  MO  =  53  MgO  -4  FeO 

» 

" 

192 

68MO-2(6R2O3-  18SiO2) 
•  42  H26 

58  MO  =  50  MgO  -8  CaO 
12R2O3=10.5A12O3-  1.5Fe2O3 

» 

>» 

193 

58M022(6R203-18Si02) 
•  46  H2O 

58  MO  =  58  MgO 
12R2O3  =  8.5A12O3-  1  .5Fe2O3-2Cr2O3 

" 

Ufalejsk 

194 

58MO-2(6R203-18Si02) 
•  46  H20 

58  MO  =  58  MgO 
12  R203  =  8.5  A1203-1.5  Fe2O3-2  Cr2O3 

n 

tt 

195 

58MO-2(6R2O3-  18SiO2) 
•  46  H2O 

58  MO  =  58  MgO 
12  R2O3  =  8.5  A12O3  -1.5Fe2O3-2  Cr2O3 

" 

" 

196 

58MO-2(6R2O8-  18SiO2) 
•  46  H2O 

58  MO  =  58  MgO 
12  R2O3  =  8.5  A12O3-1.5  Fe2O3-2  Cr2O3 

" 

Bilimbajewsk 

197 

59MO-2(6R2O3-  18SiO2) 
•  48  H20 

59  MO  =  59  MgO 
12R203=10Al203-2Fe203 

» 

Texas,  Pa. 

198 

59  MO  •  2  (6  R2O3  •  18SiO2) 
•  48  H20 

59  MO  =  59  MgO 
12R203  =  10Al203-2Fe203 

» 

Willimantic, 

Conn. 

199 

60MO-2(6R2O3-18SiO2) 
•  48  H2O 

60  MO  =  55  MgO  -  4  FeO  •  1  CaO 
12  R2O3  =  11.5  A12O3  •  0.5  Fe2O3 

i> 

Kariaet, 
Greenland 

200 

62  MO  •  2  (6  R2O3  •  18SiO2) 
•  52  H2O 

62  MO  =  54  MgO-2  FeO-4  CaO-1  K2O 
•  1  Na2O  ;  12  R2O3  =  9  Al2O3-3  Cr2O3 

» 

Unst 

201 

62MO-2(6AU)3-18Si02) 
•  46  H2O 

62  MO  =  61  .5  MgO  •  0.5  FeO 

» 

Mauleon 

202 

62MO-2(6R203-18Si02) 
•  48  H20 

62  MO  =  62  MgO 
12R203=9Al203-3Fe203 

»> 

Achmatowsk 

203 

62  MO  •  2  (6  R2O3  •  18SiO2) 
•  48  H20 

62  MO  =  62  MgO 
12  R2O3  =  9  A12O3  •  3  Fe2O3 

n 

» 

204 

63MO-2(6Al2O3-18SiO2) 
•  48  H20 

63  MO  =  53  MgO  •  8  FeO  -  2  CaO 

tt 

Kariaet, 
Greenland 

205 

64  MO  •  2  (6  A12O3  •  18  SiO2) 
•  48  H20 

64  MO  =  60  MgO  -4  FeO 

" 

Achmatowsk 

206 

64  MO  •  2  (6  A12O3  •  18SiOa) 
•48H20 

" 

» 

» 

THE   ORTHOCHLORITE   GROUP 


403 


Analyst 

SiO, 

A120S 

Fe,03 

Cr203 

FeO 

MnO 

CaO  |  MgQ 

Kao 

Na,0 

H,0 

Total 

Loretz 

Theory 

29.08  13.79 

4.33 



42.62 

— 

— 

— 

— 



10.18 

100.00 

IV 

29.00  13.00 

6.00 



42.00 

— 

— 

— 

— 

— 

10.00 

100.00 

Heddle 

Theory 

31.49  14.87 

4.67 



17.85 

1.03 

— 

17.49 





12.60 

100.00 

LXVIII 

31.03 

14.85 

5.73 

— 

17.42 

1.00 

0.36 

17.42 

— 

— 

12.48 

100.29 

it 

Theory 

31.70 

17.22 

1.17 



12.16 

— 

1.64 

20.25 





15.86 

100.00 

VI 

32.00  17.33 

1.19 



12.45 

— 

1.57 

20.42 

— 

— 

15.45 

100.41 

M 

Theory 

31.11  15.43 

3.46 



15.55 

— 

1.21 

18.73 

— 



14.51 

100.00 

VIII 

30.93 

15.32 

3.16 



15.31 

0.38 

1.38 

18.65 

— 

— 

14.69 

99.82 

Gintl 

Theory 

34.85 

18.93 

1.29 



1.16 

— 

— 

30.97 





12.78 

100.00 

XIII 

35.31 

18.28 

1.26 



0.83 

— 

— 

31.61 

— 

— 

13.26 

100.55 

van 

Theory 

33.21 

17.23 

2.46 



1.11 



0.86 

30.74 





14.39 

100.00 

Weryecke 

II 

32.84 

17.34 

3.29 



1.04 

— 

0.75 

30.48 

— 

— 

14.44 

100.18 

Komonen 

Theory 

35.12 

17.40 

3.90 



— 

— 

0.90 

33.92 

— 



8.75 

100.00 

xcv 

34.99 

17.15 

3.39 

— 

— 

— 

1.42 

34.49 

— 

8.56 

100.00 

M 

Theory 

35.12 

17.40 

3.90 



— 

— 

0.90 

33.92 

— 



8.75 

100.00 

XCVI 

34.23 

16.31 

3.33 



— 

— 

1.75 

35.36 

— 

— 

8.68 

99.66 

Hermann 

Theory 

32.62 

18.49 



4.35 

— 

— 

32.02 

— 



12.52 

100.00 

XCVII 

32.35 

18.00 

— 



4.37 

— 

— 

32.29 

— 

— 

12.50 

99.51 

Clarke  and 

Theory 

32.36 

16.05 

3.59 

—  . 

— 

— 

6.71 

29.96 

— 



11.33 

100.00 

Schneider 

CI 

32.27 

16.05 

4.26 



0.28 

— 

6.21 

29.75 

— 

— 

11.47 

100.29 

Herzog  von 

Theory 

32.14 

12.90 

3.57 

4.53 

— 

— 

— 

34.54 

— 



12.32 

100.00 

Leuchtenberg 

CII 

33.12 

13.56 

2.29 

4.19 

— 

— 

— 

35.77 

— 

— 

12.65 

101.58 

)t 

Theory 

32.14 

12.90 

3.57 

4.53 

— 

— 

— 

34.54 

— 

12.32 

100.00 

cm 

32.35 

13.29 

2.00 

4.19 

— 

— 

— 

35.04 

— 

— 

12.62 

99.49 

N.  v.  Zinn 

Theory 

32.14 

12.90 

3.57 

4.53 

— 

— 



34.54 





12.32 

100.00 

CIV 

33.31 

12.60 

2.30 

4.04 

— 

— 

— 

35.62 

— 

— 

12.62 

100.49 

M 

Theory 

32.14 

12.90 

3.57 

4.53 

— 

— 



34.54 

— 

— 

12.32 

100.00 

CVI 

32.50 

13.20 

2.30 

4.00 

— 

— 

— 

35.60 

— 

— 

12.60 

100.30 

Hermann 

Theory 

32.13 

15.15 

4.76 

— 

— 





35.10 

— 

— 

12.86 

100.00 

CXLI 

31.82 

15.10 

4.06 

0.90 

0.25  NiO 

— 

— 

35.24 

— 

— 

12.75 

100.12 

Burton 

Theory 

32.13 

15.15 

4.76 

— 

— 





35.10 



— 

12.86 

100.00 

CXLIX 

31.86 

15.80 

4.77 

— 

— 

— 

0.30 

34.30 

— 

— 

12.72 

99.75 

Hammer- 

Theory 

31.76 

16.95 

1.19 



4.23 



0.82 

32.35 





12.70 

100.00 

schlag 

CXVI 

30.34 

16.86 

1.86 

— 

4.53 

— 

0.61 

31.82 

— 

0.37 

12.70 

99.09 

Heddle 

Theory 

30.19 

12.83 

— 

6.38 

2.01 

— 

3.13 

30.19 

1.32 

0.87 

13.08 

100.00 

LXIII 

29.89 

12.93 

— 

5.97 

1.96 

— 

3.54 

29.93 

1.16 

0.97 

13.27 

99.62 

Delesse 

Theory 

31.99 

18.13 



— 

1.18 





36.44 



— 

12.26 

100.00 

LVIII 

32.10 

18.50 

— 

0.60 

— 

— 

36.70 

— 

— 

12.10 

100.00 

Struve 

Theory 

31.29 

13.30 

6.95 









35.93 





12.53 

100.00 

XCII 

31.64 

13.54 

5.83 

— 

— 

— 

0.05 

36.20 

— 

— 

12.74 

100.00 

Theory 

31.29 

13.30 

6.95 

___ 







35.93 





12.53 

100.00 

XCIII 

31.52 

13.96 

6.12 

— 

— 

— 

0.05 

35.68 

— 

— 

12.67 

100.00 

Janowsky 

Theory 

30.62 

17.34 

— 

— 

8.16 

— 

1.59 

30.04 

— 

— 

12.25 

100.04 

CXVII 

30.32 

17.90 

— 

— 

7.71 

— 

1.28 

29.88 

— 

— 

12.28 

99.37 

Kobell 

Theory 

31.14 

17.64 

— 



4.16 



— 

34.60 

0.85(Resd.) 

12.46 

100.00 

LXXXIX 

31.14 

17.14 

— 

— 

3.85 

0.53 

— 

34.40 

— 

— 

12.20 

100.11 

Varrentrapp 

Theory 

31.14 

17.64 

— 

— 

4.16 

— 

— 

34.60 

0.85(Besd.) 

12.46 

100.00 

XC 

30.38 

16.97 

— 

— 

4.37 

— 

— 

33.97 

—      — 

12.63 

98.32 

404 


THE   ORTHOCHLORITE   GROUP 


0.  Orthoehlorites  of  the  type 
R  •  Si  •  R  •  Si  •  R  =  8  R90o  •  12  SiO, 


Source 

207 

40  MO 

•2(8Fe2O3- 

12  SiO2) 

•  44  H2O 

40  MO  =  40  FeO 

Cronstedtite 

Cornwall 

208 

41  MO 

-2(8A12O8- 

12SiO2) 

•40H2O 

41  MO  =  31  FeO  -10  MgO 

Thuringite 

Lake  Superior 

P.  Orthoehlorites  of  the  type 
R  •  SAi  •  R  •  Si  •  R  =  9  R203  •  12  Si02 


209 
210 
211 
212 
213 
214 


Source 


16  MO  •  2(9  A12O3  •  12  SiO2) 
•  34  H2O 

28MO-2(9R2O3-12SiO2) 

•  30  H2O 

30MO-2(9R203-12Si02) 

•  42  H20 

33MO-2(9R2O3-12SiO2) 
•36H20 

37MO-2(9Al2O3-12SiO2) 
•34H2O 

40  MO  •  2(9  Fe2O3  •  12  SiO2) 
•46H20 


16  M0  =  14  MgO  •  1  CaO  •  1  FeO 

28  MO  =  25  FeO -3  MgO 
18R203  =  15Al203-3Fe203 

30  MO  =  28  FeO -2  MgO 
18  R2O3= 7-5  Fe2O3  •  10.5  Al 

33  MO  =  31  FeO -2  MgO 
18R203=12Al203-6Fe203 

37  MO  =  24  MgO  •  13  FeO 
40  MO  =  40  FeO 


FeO 

0 
P3 
3 
U2O3 

Rumpfite 
Aphrosiderite 
Thuringite 

St.  Michael 
Weilburg 
Schmiedefeld 

3 
P3 
3 

Orthochlorite 

Chester,  Mass. 

Cronstedtite 

Cornwall 

New  Formulae  for 
The  following  analyses  of  the  minerals 

A.  R  •  Si  •  R  =5  R2O3  •    6  Si02, 

B.  R  •  SAi  •  R  •  Si  •  R  =  8  R203  •  12  Si02, 

A.  Tourmalines  of  the  type 
R  •  Si  •  R  =  5  R203  •  6  Si02 


Source 

Analyst  * 

4  RO  •  4(5  R2O3 

•6Si02) 

4MO  =  0.5MnO-  1.5Li2O-l  Na2O-0.5K2O 

Elba 

Rammelsberg 

•4H20 

•  0.5  H2O  ;  20  R2O3=16  A12O3  •  4  B2O3 

4  RO  •  4(5  R2O3 

•  6  SiO2) 

4  MO  =0.5  CaO  •  2  Li2O  •  1.5  Na2O 

Rumford 

Riggs 

•9H20 

20  R2O3=  15.5  A12O3  •  4.5  B2O3 

5  MO  •  4(5  R203 

-  6  SiO2) 

5  MO  =  1  MnO-0.5  CaO-1.5  LiaO-1.5  Na2O 

Paris 

Rammelsberg 

•4H20 

•0.5  K2O  ;  20  R2O3=  15.5  A12O3  •  4.5  B2O3 

5  MO  •  4(5  R2O3 
•5H20 

•  6  SiO2) 

5  MO  =  1  MnO-0.5  CaO-  1.5  MgO  •  1  Li2O 
•  1  Na20  ;  20  R2O3=  16  A12O3  •  4  B2O3 

Schaitauka 

» 

5  MO  •  4(5  R2O3 

•  6  Si02) 

5MO  =  1.5FeO-0.5MgO-lLi2O-  1.5  MnO 

Elba 

n 

•5H20 

•  1.5  Na2O  ;  20  R2O3=  15  Al2O3-5  B2O3 

5  MO  •  4(5  R2O3 

•  6  SiO2) 

5  MO  =  0.5  MnO-0.5  CaO-2  Li2O  •  1  Na0O 

Schiitten- 

Scharizer 

•10H20 

•  1  K20  ;  20  R203=15.5  A12O3  •  4.5  B2O3 

hofen 

6  MO  •  4(5  R2O3 

•  6  SiO2) 

6  MO  =  1.5  FeO-1.5  MnO-0.5  CaO-0.5  Li2O 

Brazil 

Jannasch 

•7H2O 

•  2  Na2O  ;  20  R2O3=  15  A12O3  •  5  B2O3 

and  Calb 

6MO-4(5R2O3 

•  6  SiO2) 

6  MO  =  1  FeO  •  1  MnO  •  0.5  CaO  •  2  Li2O 

H 

Riggs 

•8H2O 

•  1.5Na8O  ;  20R2O3  =  14.5  Al2O3-5.5  B2O3 

*  See  references  on  p.  441 


THE  TOURMALINE   GROUP 


405 


or  the  general  formula 

m  MO  •  2  (8  R2O3  •  12  Si02) 


nHoO. 


Analyst 

1 

SiO» 

Al,03 

Fet03 

Cra08 

FeO 

MnO 

CaO 

MgO 

K,o 

Na,0 

H,0 

Total 

Flight 

Penfield 
and  Sperry 

Theory 
VIII 

Theory 
X 

18.77 
18.55 

22.28 
22.35 

25.25 
25.14 

33.36 
32.75 

— 

37.54 

38.57 

35.25 
34.39 

— 

— 

6.18 
6.41 

—  • 

— 

10.33 
10.13 

11.14 
11.25 

100.00 
100.00 

100.00 
99.54 

or  the  general  formula 

m  MO  •  2  (9  R203  •  12  Si02)  •  n  H2O. 


Analyst 

SiOa 

Alaos 

Fea03' 

CraOa 

FeO 

MnO 

CaO 

MgO 

K,0 

Na,0 

H,0 

Total 

Firtsch 

Theory 

31.48 

40.12 

— 

— 

1.57 

— 

1.22 

12.23 

— 

— 

13.38 

100.00 

I    " 

30.75 

41.66 

— 

— 

1.61 

— 

0.89 

12.09 

— 

— 

13.12 

100.12 

Sand- 

Theory 

24.36 

25.89 

8.13 



30.45 





2.03 





9.14 

100.00 

berger 

III 

24.63 

25.25 

8.50 

— 

30.61 

— 

— 

1.82 

— 

— 

9.19 

100.00 

L.  Smith 

Theory 

21.94 

16.32 

18.28 

— 

30.72 

— 

— 

1.22 

— 

— 

11.52 

100.00 

I 

22.05 

16.40 

17.66 

— 

30.78 

— 

— 

0.89 

0.14(K2O'Na,O) 

11.44 

99.36 

Kammels- 

Theory 

21.74 

18.48 

14.47 

— 

34.30 

— 

— 

1.21 

— 

— 

9.78 

100.00 

berg 

II 

22.35 

18.39 

14.86 

— 

34.34 

— 

— 

1.25 

— 

— 

9.81 

101.00 

L.  Smith 

Theory 

24.90 

31.71 

— 

— 

16.21 

— 

— 

16.60 

— 

— 

10.58 

100.00 

CXXII 

25.06 

30.70 

— 

— 

16.50 

— 

— 

16.41 

— 

— 

10.62 

99.29 

Flight 

Theory 

17.94 

— 

35.87 

— 

35.87 

— 

— 

— 

— 

— 

10.32 

100.00 

VII 

17.47 

— 

36.76 

— 

36.31 

— 

0.09 

— 

— 

— 

10.09 

100.72 

the  Tourmaline  Group 

of  this  group  conform  to  the  following  types  : 

C.  R  •  Si  •  R  •  Si  •  R  =  9  R203  •  12  Si02. 

or  the  general  formula 

m  MO  •  4  (5  R2O3  •  6  Si02)  •  n  H20 


SiO> 

B,0, 

AUG. 

Fe,0, 

FeO 

TiO, 

MnO 

CaO 

MgO 

Li.O 

Na,0 

K,0 

H,0 

Fl 

Total 

Loss  on 
Ignition 

Theory 
XX 

39.76 
38.85 

7.71 
9.52 

45.06 
44.05 

0.00 
0.00 

0.00 
0.00 

0.00 
0.00 

0.98 
0.92 

0.00 
0.00 

0.00 
0.20 

.24 
.22 

1.71 
2.00 

1.30 
1.30 

2.24 
2.41 

0.00 
0.70 

100.00 
101.17 

.__ 

Theory 
LXVIII 

39.15 
38.07 

8.54 
9.99 

42.99 
42.24 

0.00 
0.00 

0.00 
0.26 

0.00 
0.00 

0.00 
0.35 

0.76 
0.56 

0.00 
0.07 

.63 
.59 

2.53 
2.18 

0.00 
0.44 

4.40 
4.26 

0.00 
0.28 

100.00 
100.29 



Theory 
LXII 

39.01 
38.19 

8.52 
9.97 

42.83 
42.63 

0.00 
0.00 

0.00 
0.00 

0.00 
0.00 

1.92 
1.94 

0.76 
0.45 

0.00 
0.39 

.22 
.17 

2.52 
2.60 

1.27 
0.68 

1.95 
2.00 

0.00 
1.18 

100.00 
101.20 



Theory 
XXXI 

39.00 
38.26 

7.57 
9.29 

44.20 
43.97 

0.00 
0.00 

0.00 
0.00 

0.00 
0.00 

1.92 
1.53 

0.76 
0.62 

1.62 
1.62 

0.81 
0.48 

1.68 
1.53 

0.00 
0.21 

2.44 
2.49 

0.00 
0.70 

100.00 
100.70 

— 

Theory 
XIX 

38.97 
37.71 

9.45 
9.99 

41.41 

41.89 

0.00 
0.00 

0.97 
1.38 

0.00 
0.00 

2.88 
2.51 

0.00 
0.00 

0.54 
0.41 

0.82 
0.74 

2.52 
2.40 

0.00 
0.34 

2.44 
2.60 

0.00 
0.50 

100.00 
100.47 

— 

Theory 
VIII 

37.94 
38.49 

8.28 
8.25 

41.66 
41.49 

0.00 
0.00 

0.00 
0.35 

0.00 
0.00 

0.94 
0.60 

0.74 
1.82 

0.00 
0.00 

1.58 
1.68 

1.64 
1.32 

2.48 
2.14 

4.74 
4.61 

0.00 
0.43 

100.00 
100.00 

— 

Theory 
XLII 

37.63 
37.05 

9.13 
9.09 

39.98 
40.03 

0.00 
0.00 

2.82 
2.36 

0.00 
0.00 

2.78 
2.35 

0.73 
0.47 

0.00 
0.32 

0.40 
0.60 

3.24 
3.18 

0.00 
Trace 

3.29 
3.23 

0.00 
1.15 

100.00 
99.83 



Theory 
XXXVIII 

38.18 
37.39 

10.18 
10.29 

39.22 
39.65 

0.00 
0.00 

1.91 
2.29 

0.00 
0.00 

1.88 
1.47 

0.74 
0.49 

0.00 
0.00 

1.59 
1.71 

2.47 
2.42 

0.00 
0.25 

3.83 
3.63 

0.00 
0.32 

100.00 
99.91 



406 


THE   TOURMALINE   GROUP 


Source 

Analyst 

9 

6  MO 

•  4(5  R2O3  • 

6  SiO2) 

6  MO  =  1  FeO  •  1  MnO  •  0.5  CaO  •  2  Li2O 

Auburn 

Riggs 

•9H20 

•1.5  Na20  ;  20  R2O3=  14.5  Al2O3-5.5  B2O3 

10 

6  MO 

•  4(5  R2O3  • 

6  Si02) 

6  MO  =  2  FeO-0.5  CaO  •  2  Li2O  •  1.5  Na2O 

» 

» 

•9H20 

20  R2O3=  14  A12O3  •  6  B2O3 

11 

7  MO 

•  4(5  R2O3  • 

6  SiO2) 

7  MO  =  1  .5  FeO-0.5  CaO  •  4  MgO  •  1  Na2O 

N.  Issetsk 

Cossa 

•5H20 

20  R2O3  =  11.5  A12O3  -5.5  B2O3  •  3  Cr2O3 

12 

7  MO 

•  4(5  R203  • 

6  SiO2) 

7MO  =  1.5FeO-1.5MnO-0.5CaO-  1.5Li2O 

Brazil 

Jannasch 

•6H20 

•  2  Na2O  ;  20  R2O3=  14.5  A12O3  •  5.5  B2O3 

and  Calb 

13 

7  MO 

•  4(5  R203  • 

6  SiO2) 

7  MO  =  1.5  FeO-  1.5MnO-0.5CaO-2  Li2O 

M 

Riggs 

•8H2O 

•1.5  Na2O  ;  20  R2O3=14.5  A12O3  •  5.5  B2O3 

14 

7  MO 

•4(5R203- 

6  SiO2) 

7  MO  =  3.5  FeO  -  1.5  Li2O  •  2  Na2O 

Rurnford 

M 

•8H2O 

20  R2O3=  14.5  A12O3  •  5.5  B2O3 

15 

8  MO 

•  4(5  R2O3  • 

6  Si02) 

8  MO  =  3  FeO  •  0.5  MnO  •  1  MgO  •  2  Li2O 

Brazil 

Rammelsberg 

•4H2O 

•  1  .5  Na2O  ;  20  R2O3  =  14  A12O3  •  6  B2O3 

16 

8  MO 

•  4(5  R2O3  • 

6  SiO2) 

8  MO  =  4  FeO-0.5  MnO  •  1.5  Li2O  •  2  Na2O 

Auburn 

Riggs 

•9H20 

20  R2O3=  14.5  A12O3  •  5.5  B2O3 

17 

8  MO 

•  4(5  R2O3  • 

6  SiO2) 

8  MO  =  2.5  FeO-1.5  MnO-2  Li2O  •  0.5  K2O 

Schiitten- 

Scharizer 

•10H20 

•1.5  Na2O  ;  20  R2O3=  15.5  Al2O3-4.5  B2O3 

hofen 

18 

10  MO 

•  4(5  R2O3  • 

6  Si02) 

10  MO  =  3  FeO-0.5  MnO-4  MgO-0.5  K2O 

M.  Bisch 

Sommerland 

•2H20 

•  2  Na2O  ;  20  R2O3  =  14  A12O3  •  6  B2O3 

19 

10  MO 

•4(5R203- 

6  SiO2) 

10  MO  -7.  5  FeO-  1.5  MgO-  1  Na2O 

Saar 

Rammelsberg 

•3H20 

20  R2O3=  14  A12O3  •  6  B2O3 

20 

10  MO 

•  4(5  R203  • 

6  SiO2) 

10MO  =  6.5FeO-lMgO-0.5MnO-  1  Li2O 

Goshen 

w 

•5H2O 

•  1  Na2O  ;  20  R2O3=  13  A12O3  •  7  B2O3 

21 

10  MO 

•  4(5  R203  • 

6  Si02) 

10  MO  =  8  FeO  •  1  MgO  •  1  Na2O 

Auburn 

Riggs 

•8H20 

20  R2O3=  13  A12O3  •  7  B2O3 

22 

10  MO 

•  4(5  R203  • 

6  SiO2) 

10  MO  =  7  FeO-  1.5  MgO-  1.5NaaO 

Paris 

•8H20 

20  R2O3  =  14.5  A12O3  •  5.5  B2O3 

23 

10  MO 

•  4(5  R203  • 

6  Si02) 

10  MO  =  7.5  FeO  -1.5  MgO-  1  Na2O 

Alabaschka 

Jannasch 

•8H2O 

20  R2O3  =  13.5  A12O3  •  6.5  B2O3 

and  Calb 

24 

12  MO 

•4(5R2O3- 
•2H2O 

6  Si02) 

12  MO  =  8.5  FeO-0.5  MnO  -2  MgO-0.5  Na2O 
•  0.5  H2O  ;  20  R2O3=  12  A12O3  •  8  B2O3 

M 

Rammelsberg 

25 

12  MO 

•  4(5  R203  • 

6  Si02) 

12  MO  =  8.5  FeO  •  1.5  MgO  •  2  Na2O 

Mursinka 

Jannasch 

•6H20 

20  R2O3=  14  A12O3  •  6  B2O3 

and  Calb 

20 

12  MO 

•  4(5  R203  • 

6  Si02) 

12  MO  =  4.5  FeO  •  5.5  MgO  •  0.5  CaO 

Stony 

Riggs 

•8H20 

•  1.5  Na2O  ;  20  R2O3=  13.5  A12O3  •  6.5  B2O3 

27 

12  MO 

•  4(5  R203  • 

6  Si02) 

12  MO  =  6  FeO  •  4  MgO  •  2  Na2O 

Piedra 

Jannasch 

•8H20 

20  R2O3=  13  A12O3  •  6  B2O3  •  1  Fe2O3 

and  Calb 

B.  Tourmalines  of  the  type 

R  •  Si  •  R  •  Si  •  R  =  8  R203  •  12  Si02 


Source 

Analyst 

28 

7  MO 

•2(8R203- 

12  Si02) 

7  MO  =  3  FeO  •  0.5  CaO  •  1  MgO  •  0.5  K2O 

Waldheim 

Sauer 

•6H2O 

•  2  Na20  ;  16  R2O3=  14  A12O3  •  2  B2O3 

29 

13  MO 

•  2(8  R203  • 

12  SiO2) 

13  MO  =  2  FeO  •  1  CaO  •  9  MgO  •  1  Na2O 

Monroe 

Rammelsberg 

•6H20 

16  R2O3  =  11.5  A12O3  •  4.5  B2O3 

30 

14  MO 

•2(8R2O3- 

12  Si02) 

14  MO  =  5  FeO  •  0.5  MnO-0.5  CaO-6.5  MgO 

Elba 

»» 

•5H2O 

•  1.5Na2O;  16  R2O3  =  11  A12O3  •  5  B2O3 

31 

14  MO 

•2(8R2O3- 

12SiO2 

14MO  =  4.5FeO-  1.5  CaO  •  7  MgO-1  Na2O 

Tamatave 

Jannasch 

•6H2O 

16R2O3=10A12O3-4.5B2O3-  1.5Fe2O3 

and  Calb 

THE   TOURMALINE   GROUP 


407 


Si02 

B203 

A120S 

Fe2os 

FeO 

Ti02 

MnO 

CaO 

Mgo 

Li2o 

Na20 

K20 

H2o 

Fl 

Total 

Loss  on 
Ignition 

Theory 
LXIV 

38.02 
38.14 

10.14 
10.25 

39.03 
39.60 

0.00 
0.30 

1.90 
1.38 

0.00 
0.00 

1.87 
1.38 

0.73 
0.43 

0.00 
Trace 

1.58 
1.34 

2.45 
2.36 

0.00 
0.27 

4.28 
4.16 

0.00 
0.62 

100.00 
100.23 

4.09 

Theory 
LXV 

38.16 
37.85 

11.10 
10.55 

37.84 
37.73 

0.00 
0.42 

3.82 
3.88 

0.00 
0.00 

0.00 
0.51 

0.74 
0.49 

0.00 
0.04 

1.59 
1.34 

2.46 
2.16 

0.00 
0.62 

4.29 
4.18 

0.00 
0.62 

100.00 
100.39 

— 

Theory 
XXXII 

36.91 
36.79 

9.84 
9.51 

30.06 
30.56 

11.70Cr203 
10.86Cr2O3 

2.77 
2.91 

0.00 
0.00 

0.00 
Trace 

0.72 
0.72 

4.10 
4.47 

1.59 
1.36 

0.00 
0.00 

0.00 

Trace 

2.31 
2.25 

0.00 
0.65 

100.00 
100.08 

— 

Theory 
XLI 

37.68 
37.40 

10.05 
10.74 

38.69 
39.02 

0.00 
0.00 

2.82 
2.35 

0.00 
0.00 

2.79 
2.57 

0.73 
0.60 

0.00 
0.20 

1.17 
1.33 

3.25 
3.59 

0.00 
0.29 

2.82 
3.08 

0.00 
0.98 

100.00 
102.15 

z 

Theory 
XXXIX 

37.48 
36.91 

9.99 
9.87 

38.49 
38.13 

0.00 
0.31 

2.81 
3.19 

0.00 
0.00 

2.77 
2.22 

0.73 
0.38 

0.00 
0.04 

1.56 
1.61 

2.42 
2.70 

0.00 
0.28 

3.75 
3.64 

0.00 
0.14 

100.00 
99.42 

3.62 

Theory 
LXIX 

37.21 
36.53 

9.93 
10.22 

38.23 
38.10 

0.00 
0.00 

6.51 
6.43 

0.00 
0.00 

0.00 
0.32 

0.00 
0.34 

0.00 
0.00 

1.19 
0.95 

3.21 

2.86 

0.00 
0.38 

3.72 
3.52 

0.00 
0.16 

100.00 
99.81 

3.31 

Theory    37.86 
XXXVI  38.06 

11.02 
10.09 

37.55 
37.81 

0.00 
0.00 

5.68 
5.83 

0.00 
0.00 

0.93 
1.13 

0.00 
0.00 

1.05 
0.92 

1.58 
1.30 

2.44 
2.21 

0.00 
0.42 

1.89 
2.23 

0.00 
0.70 

100.00 
100.70 

— 

Theory 
LXVI 

36.39 
36.26 

9.70 
9.94 

37.37 

36.68 

0.00 
0.15 

7.28 
7.07 

0.00 
0.00 

0.90 
0.72 

0.00 
0.17 

0.00 
0.16 

1.14 
1.05 

3.13 

2.88 

0.00 
0.44 

4.09 
4.05 

0.00 
0.71 

100.00 
100.28 

- 

Theory 
VII 

35.99 
36.38 

7.85 
8.12 

39.50 
39.77 

0.00 
0.00 

4.50 
4.17 

0.00 
0.00 

2.66 
2.83 

0.00 
0.00 

0.00 
0.00 

1.50 
1.54 

2.33 
1.93 

1.17 
0.93 

4.50 
4.29 

0.00 
0.00 

100.00 
100.00 

- 

Theory 
XXXIV 

36.87 
36.86 

10.74 
10.56 

36.56 
36.72 

0.00 
0.00 

5.53 
5.66 

0.00 
0.00 

0.91 
0.66 

0.00 
0.34 

4.10 
3.92 

0.00 
0.00 

3.17 
3.57 

1.20 
1.11 

0.92 
1.16 

0.00 
0.61 

100.00 
101.17 

— 

Theory 
X 

35.97 
36.11 

10.47 
11.64 

35.67 
35.46 

0.00 
0.00 

13.49 
13.17 

0.00 
0.00 

0.00 
0.28 

0.00 
0.00 

1.50 
1.52 

0,00 
0.00 

0.55 
0.98 

0.00 
0.09 

1.35 
1.26 

0.00 
0.41 

100.00 
100.92 

— 

Theory 
LVIII 

36.18 
36.22 

12.28 
10.65 

33.31 
33.35 

0.00 
0.00 

11.75 
11.95 

0.00 
0.00 

0.89 
1.25 

0.00 
0.00 

1.00 
0.63 

0.75 
0.84 

1.56 
1.75 

0.00 
0.40 

2.26 
2.21 

0.00 
0.82 

100.00 
100.07 



Theory 
LXVII 

35.04 
34.99 

10.20 
9.63 

34.76 
33.96 

- 

14.02 
14.23 

- 

0.06 

0.15 

0.97 
1.01 

Trace 

1.51 
2.01 

0.34 

3.50 
3.62 

0.00 

100.00 
100.00 

2.17 

Theory 
LXIII 

35.09 
35.03 

9.34 
9.02 

36.04 
34.44 

1.13 

12.28 
12.10 

— 

0.00 
0.08 

0.00 
0.24 

.46 
.81 

0.00 
0.07 

2.27 
2.03 

0.25 

3.50 
3.69 

0.00 

100.00 
99.89 

2.30 

Theory 
XXVIII 

35.32 
35.41 

11.14 
10.14 

33.78 
33.75 

— 

13.25 
13.42 

— 

Trace 

0.17 

.47 
.57 

~ 

1.52 

2.08 

0.34 

3.53 
3.41 

0.28 

100.00 
100.57 

Theory 
XXVII 

35.76 
36.19 

13.88 
12.79 

30.40 
30.40 

— 

15.20 
15.59 

0.88 
0.54 

~ 

.98 
.88 

0.77 
1.04 

0.47 

1.11 
1.11 

0.76 

100.00 
100.76 



Theory 
XXIX 

34.35 

34.88 

9.99 
8.94 

34.07 
34.58 

- 

14.62 
14.40 

0.27 

0.24 

0.20 

.43 
1.32 

~ 

2.96 
2.70 

0.05 

2.58 

2.87 

0.51 

100.00 
100.96 



Theory 
XLIV 

35.30 
35.56 

11.12 
10.40 

33.75 
33.38 

— 

7.94 
8.43 

0.55 

0.04 

0.69 
0.53 

5.39 
5.44 

Trace 

2.28 
2.16 

0.24 

3.53 
3.63 

0.00 

100.00 
100.36 

2.86 

Theory 
XLIII 

34.24 
34.73 

9.96 
9.64 

31.53 
31.69 

3.81 
3.18 

10.28 
10.14 

0.30 

0.16 

0.36 

3.81 
3.47 

— 

2.95 
2.85 

0.15 

3.42 
3.44 

0.47 

100.00 
100.58 

— 

or  the  general  formula 

m  MO  •  2  (8  R2O3  •  12  Si02)  •  n  H20. 


Si02 

B2O3 

Al,0,  |Fe203|  FeO 

Ti02 

MnO 

CaO 

MgO 

Li2o  Na2o 

K20 

H2o 

Fl 

Total 

Theory 

36.64 

3.55 

36.33 



5.49 



_ 

0.71 

10.18 



3.15 

1.19 

2.76 

— 

100.00 

III 

36.35 

4.61 

35.76 

— 

4.78 

0.41  SnO2 

— 

0.47 

10.01 

— 

3.89 

1.22 

2.87 

— 

99.67 

Theory 

39.38 

8.59 

32.07 



3.94 





1.54 

9.84 

— 

1.69 

— 

2.95 

— 

100.00 

LIII 

39.01 

8.95 

31.18 

— 

4.07 

— 

— 

1.81 

9.90 

— 

1.82 

0.44 

2.82 

— 

100.00 

Theory 

38.13 

9.24 

29.71 



9.53 



0.94 

0.74 

6.87 



2.46 

— 

2.38 

— 

100.00 

XVII 

38.20 

9.03 

30.02 

— 

9.93 

— 

0.58 

0.74 

6.87 

— 

2.19 

0.25 

2.29 

0.15 

100.15 

Theory 

37.19 

8.12 

26.34 

6.20 

8.37 





2.16 

7.23 

— 

1.60 

— 

2.80 

— 

100.00 

LXXIII 

35.48 

9.49 

25.83 

6.68 

7.99 

1.22 

Trace 

2.03 

6.90 

— 

1.92 

0.29 

2.58 

0.33 

100.74 

408 


THE   TOURMALINE    GROUP 


Source 

Analyst 

32 

15  MO 

•  2(8  R203  • 

12SiO2) 

15  MO  =  4.5  FeO  •  1  CaO  •  8  MgO  •  0.5  K2O 

Haddam 

Rammels- 

•4H20 

•  1  Na2O  ;  16  B2O8=  11.5  A12O3  •  4.5  B2O3 

berg 

33 

15  MO 

•  2(8  R203  • 

12SiO2) 

15  MO  =  2  FeO  •  0.5  CaO-11  MgO-1.5  Na2O 

Eibenstock 

it 

•6H2O 

16  R2O3=11.5  A12O3  •  4.5  B2O3 

34 

16  MO 

•  2(8  R203  • 

12  Si02) 

16  MO  =  6  FeO  •  0.5  CaO  •  8  MgO  •  0.5  K2O 

Snarum 

?> 

•4H2O 

•  1  Na2O  ;  16  R2O3=  11  A12O3  •  5  B2O3 

35 

16  MO 

•  2(8  R203  • 

12  SiOa) 

16  MO  =  0.5  FeO-1  CaO-14  MgO-0.5  Na2O 

Gouverneur 

H 

•5H20 

16  R2O3=  11.5  A1203  •  4.5  B2O3 

36 

17  MO 

•  2(8  R203  • 

12  SiO2) 

17  M0  =  0.5  FeO-2  CaO-13.5  MgO-1  Na2O 

,, 

Riggs 

•8H20 

16  R2O3=  10.5  A12O3  •  5.5  B2O3 

37 

18  MO 

•  2(8  R2O3  • 

12SiO2) 

18  MO  =  0.5  FeO-2.5  CaO-14  MgO-1  Na2O 

Dekabb 

M 

•8H2O 

16  R2O3=  11  A12O3  •  5  B2O3 

38 

19  MO 

•  2(8  R2O3  • 

12SiO2) 

19  MO  =  4.5  FeO-2.5  CaO-11  MgO-1  Na2O 

Pierrepont 

If 

•8H2O 

16  R2O3  =  10  A12O3  •  6  B2O3 

C.  Tourmalines  of  the  type 
R  -  SAi  •  R  •  Si  •  R  =  9  R203  -  12  Si02 


Source 

Analyst 

39 

3  MO  •  2(9  R203  • 

12SiO2) 

3  MO  =  0.5  MnO-0.5  MgO-1  Na2O-l  K2O 

Rozna 

Rammels- 

•5H20 

18  R2O3=  14  A12O3  •  4  B2O3 

berg 

40 

5  MO  •  2(9  R2O3  • 

12Si02) 

5  MO  =  2.5  FeO-0.5  MnO-0.5  MgO-1.5  Na2O 

Campol 

Engel- 

•5H2O 

18  R2O3  =  13.5  A12O3  •  4.5  B2O3 

mann 

41 

8  MO  •  2(9  R2O3  • 

12  SiO2) 

8  MO  =  3.5  FeO-  0.5  MnO-  1.5MgO-lLi2O 

Chester- 

Rammels- 

•5H20 

•  1.5  Na2O  ;  18  R2O3=  13.5  Al2O3-4.5  B2O3 

field 

berg 

42 

10  MO  •  2(9  R2O3  • 

12  Si02) 

10  MO  =  5.5  FeO  •  1.5  MnO-1  MgO-1.5  Na2O 

Sarapulka 

H 

•3H2O 

•  0.5  H2O  ;  18  R2O3  =  11.5  A12O3  •  6.5  B2O3 

43 

10MO-2(9R203- 

12  Si02) 

10  MO  =  5.5  FeO-1  MnO-1.5  MgO-1.5  Na2O 

Elba 

M 

•4H20 

•  0.5  K2O  ;  18  R2O3=  13  A12O3  •  5  B2O3 

44 

11MO-2(9R2O3- 

12Si02) 

11  MO  =  8  FeO  •  0.5  MgO  •  2.5  Na2O 

Buchw. 

Jannasch 

•8H2O 

18  R2O3=  13.5  A12O3  •  4.5  B2O3 

and  Calb 

45 

11MO-2(9R203- 

12SiO2) 

11  MO  =  9  MgO  •  1.5  Na2O  •  0.5  CaO 

Maryland 

Gill 

•8H20 

18R2O3=12.5A12O3-4.5B2O3-  1  Cr2O3 

46 

11MO-2(9R203- 

12SiO2) 

11  MO  =  4.5  FeO  •  0.5  CaO  •  4  MgO-  2  Na2O 

Tamaya 

Schwarz 

•9H20 

18  R2O3  =  12.5  A12O3  •  5.5  B2O3 

47 

12MO-2(9R2O3- 

12  SiO2) 

12  MO  =  6.5  FeO-0.5  CaO-3.5  MgO-1  Na2O 

Langenb. 

Rammels- 

•3H2O 

•  0.5  K20  ;  18  R203  =  12  A12O3  •  6  B2O3 

berg 

48 

12MO-2(9R2O3- 

12SiO2) 

12  MO  =  6.5  FeO  •  0.5  CaO  •  4  MgO  •  1  Na2O 

Krumrn 

,, 

•3H2O 

18R203=13A1203-5B203 

49 

12MO-2(9R2O3- 

12  SiO2) 

12  M0  =  9.5  FeO  •  0.5  CaO  •  1  MgO  •  1  Na2O 

Andreasb. 

,, 

•4H20 

18R203=12A1203-6B203 

50 

12  MO  •  2(9  R2O3  - 

12SiO2) 

12  MO  =  7.5  FeO-0.5  CaO-2.5  MgO-0.5  K2O 

Bovey 

» 

•4H20 

•  1  Na2O  ;  18  R2O3  =  11.5  AlaO3  •  6.5  B2O3 

Tracey 

51 

12MO-2(9R2O3- 

12SiO2) 

12  MO  =  7  FeO  •  0.5  CaO  •  2.5  MgO  •  1  MnO 

Krumm 

„ 

•5H20 

•  1  Na2O  ;  18  R2O3=  12.5  Al2O3-5.5  B2O3 

52 

12  MO  •  2(9  R2O3  • 

12  SiO2) 

12  M0  =  1.5  FeO-0.5  CaO-8.5  MgO-0.5  K2O 

Texas 

,, 

•6H2O 

•  1  Na2O  ;  18  R2O3=  13  A12O3  •  5  B2O3 

63 

12MO-2(9R2O3- 

12  SiO2) 

12  MO  =  8  FeO  -  0.5  CaO  •  2  MgO  •  1.5  Na2O 

Brazil 

Biggs 

•8H2O 

18R203=13A1203-5B2O3 

54 

12MO-2(9R2O3- 

12  SiOa) 

12  MO  =  7.5  FeO  •  1  MnO  •  1.5  MgO-0.5  K2O 

Schutten- 

Scharizer 

•9H20 

1.5  Na20  ;  18  R2O3=  14  A12O3  •  4  B2O3 

hofen 

THE   TOURMALINE   GROUP 


409 


SiO» 

Bao, 

AlgOs 

Feaoa 

FeO 

TiO» 

MnO 

CaO 

MgO 

Li,o 

Na»o 

K,0 

H,o 

Fl 

Total 

Loss  on 
Ignition 

Theory 
LV 

37.81 
37.50 

8.25 
9.02 

30.80 
30.87 

— 

8.52 
8.54 

z 

z 

1.47 
1.33 

8.40 
8.60 

z 

1.63 
1.60 

1.23 
0.73 

1.89 
1.81 

— 

100.00 
100.00 

— 

Theory 
II 

38.50 
37.75 

8.40 
9.14 

31.36 
30.86 

- 

3.85 
4.36 

~ 

- 

0.75 
0.88 

11.76 
11.62 

z 

2.49 
2.27 

0.30 

2.89 
2.82 

— 

100.00 
100.00 

____^ 

Theory 
XXV 

37.20 
37.22 

9.02 
9.73 

28.98 
30.00 

— 

11.16 
11.16 

~ 

- 

0.72 
0.65 

8.26 
7.94 

- 

1.60 
1.13 

1.21 
0.53 

1.85 
1.64 

0.55 

100.00 
100.55 

Theory 
XLVII 

38.91 
38.85 

8.49 
8.35 

31.70 
31.32 

z 

0.98 
1.14 

~ 

- 

1.51 
1.60 

15.13 
14.89 

— 

0.84 
1.28 

0.26 

2.44 
2.31 

~ 

100.00 
100.00 

z 

Theory 
XLIX 

38.00 
37.39 

10.14 
10.73 

28.26 

27.79 

0.10 

0.95 
0.64 

1.19 

— 

2.96 

2.78 

14.25 
14.09 

Trace 

1.64 
1.72 

0.16 

3.80 
3.83 

Trace 

100.00 
100.42 

— 

Theory 
LII 

37.37 

36.88 

9.06 
10.58 

29.12 

28.87 

— 

0.93 
0.52 

0.12 

— 

3.63 
3.70 

14.54 
14.53 

Trace 

1.61 
1.39 

0.18 

3.74 
3.56 

0.50 

100.00 
100.83 

— 

Theory 
L 

36.09 
35.61 

10.50 
10.15 

25.57 
25.29 

0.44 

8.12 
8.19 

0.55 

Trace 

3.51 
3.31 

11.03 
11.07 

Trace 

1.55 
1.51 

0.20 

3.63 
3.34 

0.27 

100.00 
99.93 

2.69 

or  the  general  formula 

m  MO  •  2  (9  R203  -  12  Si02)  •  n  H20. 


SiOa 

B8o, 

Al,0, 

Fe20, 

FeO 

TiO, 

MnO 

CaO 

MgO 

Li,0  JNa,C 

>  K,0 

H.OJ  Fl 

Total 

Theory 
IX 

41.75 
41.16 

8.10 
8.93 

41.40 
41.83 

— 

— 

— 

1.03 
0.95 

— 

0.58 
0.61 

0.41 

1.80 
1.37 

2.73 
2.17 

2.61 
2.57 

1.19 

100.00 
101.19 

Theory 
XV 

40.57 
39.26 

8.86 
9.40 

38.80 
38.33 

— 

5.06 
4.51 

— 

1.00 
1.12 

— 

0.56 
1.02 

— 

2.61 
2.43 

0.38 

2.54 
2.41 

0.61 

100.00 
99.46 

Theory 
LVII 

39.01 
38.46 

8.51 
9.73 

37.29 
36.80 

— 

6.83 
6.38 

— 

0.96 
0.78 

1.63 

1.88 

0.81 
0.72 

2.52 
2.47 

0.47 

2.44 
2.31 

0.55 

100.00 
100.55 

Theory 
XXX 

38.24 
38.30 

12.06 
11.62 

31.15 
31.53 

— 

10.52 
10.30 

— 

2.83 
2.68 

1.06 
1.06 

— 

2.47 
2.37 

0.33 

1.67 
1.81 

0.80 

100.00 
100.80 

Theory 
XVIII 

37.35 
37.14 

9.06 
9.37 

34.41 
34.15 

— 

10.28 
10.52 

— 

1.84 
1.87 

1.56 
1.68 

0.32 

2.41 
2.30 

1.22 
0.75 

1.87 
1.90 

0.47 

100.00 
100.47 

Theory 
XXXIII 

35.77 
35.50 

7.80 
8.34 

34.20 
34.39 

- 

14.30 
14.26 

Trace 

Trace 

0.50 
0.51 

Trace 

3.85 
3.43 

— 

3.58 
3.34 

0.77 

100.00 
100.54 

Theory 
XLV 
Theory 
XXXV 

37.83 
36.56 

36.96 
36.34 

8.25 
8.90 

9.86 
10.87 

33.49 
32.58 

32.72 
32.22 

4.00  Cr20, 
4.32Cr203 

0.79Fe203 

8.30 
8.31 

0.09 

Trace 

0.74 
0.75 

0.72 
0.79 

9.46 
9.47 

4.10 
3.92 

Trace 

2.44 
2.22 

3.18 
3.14 

0.13 
0.22 

3.78 
3.74 

4.16 
3.89 

0.06 

100.00 
99.70 

100.00 
99.70 

Theory 
IV 

37.09 
37.24 

10.79 
11.02 

31.53 
31.63 

— 

12.06 
11.64 

___ 

~ 

0.72 
0.62 

3.61 
3.65 

~ 

1.60 
1.93 

1.21 

0.82 

1.39 
1.45 

— 

100.00 
100.00 

Theory 
V 

37.05 
36.43 

8.98 
9.82 

34.11 
34.12 

- 

12.04 
11.58 

- 

— 

0.72 
0.44 

4.12 
3.84 

- 

1.59 
1.36 

0.30 

1.39 
2.11 

— 

100.00 
100.00 

Theory 
I 

36.28 
36.06 

10.56 
11.11 

30.84 
30.34 

— 

17.23 
17.40 

- 

0.11 

0.71 
0.72 

1.00 
0.78 

~ 

1.56 
1.36 

0.58 

1.82 
1.54 

0.85 

100.00 
100.85 

Theory 
XXI 

36.77 
37.94 

11.60 
10.72 

29.96 
30.22 

___ 

13.79 
13.82 

- 

0.40 

0.71 
0.50 

2.55 
2.62 

~ 

1.58 
1.39 

1.20 
0.65 

1.84 
1.74 

0.45 

100.00 
100.45 

Theory 
XII 

36.42 
36.25 

9.71 
10.27 

32.24 
32.21 

— 

12.75 
12.82 

— 

1.80 
1.50 

0.70 
0.40 

2.53 

2.32 

— 

1.57 
1.43 

0.46 

2.28 
2.34 

0.64 

100.00 
100.64 

Theory 
XLVII 

37.81 
38.45 

9.17 

8.57 

34.82 
34.56 

— 

2.84 
2.98 

0.09 

— 

0.73 
0.71 

8.93 
9.11 

— 

1.62 
2.00 

1.23 
0.73 

2.84 
2.80 

— 

100.00 
100.00 

Theory 
XL 

35.68 
34.63 

8.65 
9.63 

32.86 
32.70 

0.31 

14.27 
13.67 

— 

0.12 

0.69 
0.33 

1.98 
2.13 

0.08 

2.30 
2.11 

0.24 

3.57 
3.49 

0.06 

100.00 
99.52 

Theory 
VI 

34.95 
35.10 

6.78 
7.09 

34.65 
35.10 

.. 

13.10 
13.36 

0.08  SnO2 

1.72 
1.48 

— 

1.46 
0.98 

~ 

2.26 
1.92 

1.14 

0.88 

3.94 
4.01 

__ 

100.00 
100.00 

410 


THE   TOURMALINE   GROUP 


Source 

Analyst 

55 

13  MO 

•  2(9  R203  • 
•5H20 

12SiO2) 

13  MO  =  7  FeO-0.5  MnO-3.5  MgO-1.5  Na2O 
•0.5H2O;  18R2O3=12A12O3-  6B2O3 

Dekalb 

Rammels- 
berg 

50 

13  MO 

•2(9R203- 
•6H20 

12  SiO2) 

13  MO  =  1.5  FeO  •  10  MgO  •  1.5  Na2O 
18  R2O3  =  12  A12O3  •  6  B2O3 

Zillertal 

5» 

57 

13  MO 

•  2(9  R203  • 
•  6  H20  • 

12  SiO2) 

13  MO=4  FeO  •  1  CaO  •  7  MgO  •  1  Na2O 
18R203=12A1203-6B203 

St.  Gott- 
hard 

»> 

58 

13  MO 

•  2(9  R203  • 
•6H20 

12SiO2) 

13  MO  =  1.5  FeO-0.5  CaO-10  MgO-1  Na2O 
18  R2O3=  12.5  A12O3  •  5.5  B2O3 

Orford 

n 

59 

13  MO 

•  2(9  R2O3  • 
•8H2O 

12  SiO2) 

13  MO  =  2  FeO  -0.5  CaO-9  MgO-1.5  Na2O 
18  R2O3=  12  A12O3  •  6  B2O3 

Monroe 

Riggs 

GO 

14  MO 

•  2(9  R2O3  • 
•4H2O 

12  Si02) 

14  MO  =  0.5  FeO-1  CaO-11  MgO-1.5  Na2O 
18R203=12A1203-6B203 

Dobrawa 

Raminels- 
berg 

61 

14  MO 

•  2(9  R203  • 
•6H20 

12  Si02) 

14MO  =  2.5FeO-lCaO-9MgO-1.5Na2O 
18R203=13A1203-5B203 

Godhaab 

- 

62 

14  MO 

•  2(9  R203  • 
•7H20 

12  Si02) 

14  MO  =  3  FeO  •  1  CaO  •  8  MgO  •  2  Na2O 
18  R203=  12  A1203  •  5  B203  •  1  Fe2O3 

Ohlapian 

Jannasch 

63 

HMO 

•2(9R203- 
•8H2O 

12SiO2) 

UMO  =  1.5FeO-  1  CaO-10MgO-1.5Na2O 
18  R2O3=  12.5  A12O3  •  5.5  B2O3 

Orford 

Riggs 

64 

14  MO 

•2(9R203- 
•8H20 

12Si02) 

14  MO  =  7  FeO-0.5  CaO-4.5  MgO-1.5Na2O 
•  0.5  H2O  ;  18  R2O3  =  12.5  Al2O3-5.5  B2O3 

Haddam 

" 

65 

15  MO 

•2(9R203- 
•5H20 

12SiO2) 

15  MO  =  4  FeO-0.5  CaO-9.5  MgO-1  Na2O 
18  R2O3=  12  A12O3  •  6  B2O3 

Kragerfi 

Rammels- 
berg 

66 

15  MO 

•  2(9  R203  • 
•6H2O 

12SiO2) 

15  M0  =  3.5  FeO-1.5  CaO-8  MgO-2  Na2O 
18  R2O3=  11.5  A12O3  •  6  B2O3-0.5  Fe2O3 

Snarum 

Jannasch 
and  Calb 

67 

15  MO 

•2(9R203- 
•8H20 

12SiO2) 

15  MO  =  4.5  FeO-1.5  CaO-8  MgO-1  Na2O 
18  R2O3=  12  A12O3  •  6  B2O3 

Baffins- 
land 

Riggs 

6S 

16  MO 

•2(9R2O3- 
•4H20 

12  Si02) 

16  MO  =  7.5  FeO-0.5  CaO-6.5  MgO-1.5Na2O 
18R203=12A1208-6B203 

Unity 

Rammels- 
berg 

69 

20  MO 

•  2(9  R203  • 
•7H20 

12Si02) 

20  MO  =  0.5  FeO-4  CaO-15  MgO-0.5  Na2O 
18  R2O3=11.5  A12O3  •  6.5  B2O3 

Hambg. 

Riggs 

The  Fel- 

The  following  analyses  of  the  minerals  of  the 

A.  Si  •  R  •  SAi  •  Si  •  R  •  Si  =  5  R203  •  22  Si02, 

B.  Si  •  R  •  Si  •  Si  •  R  •  Si  =  5  R203  •  24  Si02, 
C.  Si  •  R  •  Si  •  Si  •  R  •  Si  =  6  R203  •  20  Si02, 

A.  Felspars  of  the  type 
Si  •  R  •  Si  •  Si  •  R  •  Si  =  5  R203  •  22  Si02 


1 

Source 

1 

3  MO 

•  5  R2O3 

22  SiO2 

3MO  =  1 

5  Na2O-0.5  CaO-0.5  MgO  •  0.5  K2O 

Oligoclase 

Cape  Wrath 

•  1H2O 

5R 

2O3=4.75  A12O3  •  0.25  Fe2O3 

2 

4  MO 

•  5  R2O3 

22  SiO2 

4MO  = 

=  1.5  Na2O  •  1.75  CaO  •  0.5  MgO 

Andesine 

Ale  bei 

•2H2O 

•0.25K2O 

Lima 

3 

4  MO 

•  5  A1203 

•  22  SiO2 

4MO  = 

1.75  Na2O  •  1.75  CaO  •  0.25  MgO 

w 

Marmato  bei 

•  1  H2O 

•  0.25  K2O 

Popayan 

THE   FELSPAR   GROUP 


411 


SiO, 

B,0, 

A1.0, 

FejO, 

FeO 

Ti02 

MnO 

CaO 

MgO 

Li2o 

Na20 

K»0 

H20 

Fl 

Total 

Loss  on 
Ignition 

Theory 

36.42 

10.60 

30.95 



12.74 



0.90 



3.54 

— 

2.35 



2.50 



100.00 

— 

LI 

37.07 

9.70 

31.86 

— 

12.55 

— 

0.51 

— 

3.49 

— 

2.04 

0.30 

2.48 

0.31 

100.31 

— 

Theory 

37.97 

11.05 

32.28 



2.85 



— 



10.55 

— 

2.45 



2.85 



100.00 

— 

XIV 

38.51 

9.52 

32.65 

— 

2.80 

— 

0.36 

0.16 

10.46 

— 

2.13 

0.37 

3.04 

0.36 

100.36 

— 

Theory 

37.14 

10.87 

31.57 



7.43 





1.44 

7.21 

— 

1.60 



2.80 



100.00 



XVI 

38.00 

10.32 

31.41 

— 

7.23 

— 

— 

1.31 

7.27 

— 

1.43 

0.28 

2.75 

— 

100.00 

— 

Theory 

37.84 

10.09 

33.51 



2.84 



— 

0.74 

10.51 

— 

1.63 



2.84 



100.00 

— 

LIX 

38.33 

9.86 

33.15 

— 

2.88 

— 

— 

0.77 

10.89 

— 

— 

— 

2.81 

— 

100.21 

Theory 

37.38 

10.80 

31.78 



3.74 



— 

0.73 

9.35 

— 

2.40 



3.74 



100.00 



LIV 

36.41 

9.65 

31.27 

— 

3.80 

1.61 

Trace 

0.98 

9.47 

— 

2.68 

0.21 

3.79 

— 

99.87 

3.59 

Theory 

38.09 

11.08 

32.38 



0.95 





1.48 

11.64 

— 

2.46 



1.92 



100.00 



XIII 

38.09 

11.15 

32.90 

— 

0.66 

— 

— 

1.25 

11.79 

2.37 

0.47 

2.05 

0.64 

101.37 

— 

Theory 

36.81 

8.93 

33.89 



4.60 





.43 

9.20 

2.38 



2.76 

— 

100.00 

— 

LXXII 

37.70 

7.82 

34.26 

— 

4.42 

— 

— 

.25 

9.51 

— 

2.00 

0.43 

2.61 

— 

100.00 

— 

Theory 

35.87 

8.70 

30.48 

3.98 

5.38 

— 

— 

.39 

7.97 

— 

3.09 

— 

3.14 

— 

100.00 

— 

XI 

35.69 

9.84 

30.79 

3.65 

5.46 

0.86 

Trace 

.54 

8.12 

— 

2.53 

0.27 

3.12 

— 

101.95 

— 

Theory 

36.92 

9.85 

32.69 

— 

2.77 



— 

.44 

10.26 

— 

2.38 

— 

3.69 

— 

100.00 

— 

LX 

36.66 

10.07 

32.84 

— 

2.50 

0.23 

Trace 

.35 

10.35 

Trace 

2.42 

— 

3.78 

Trace 

100.42 

— 

Theory 

35.51 

9.47 

31.42 

— 

12.42 





0.69 

4.43 

— 

2.29 



3.77 



100.00 

— 

LVI 

34.95 

9.92 

31.11 

— 

11.87 

0.57 

0.09 

0.81 

4.45 

Trace 

2.22 

0.24 

3.62 

— 

100.35 

2.41 

Theory 

36.63 

10.66 

31.14 



7.33 





0.71 

9.67 



1.57 



2.29 

100.00 

— 

XXIV 

37.11 

9.29 

31.26 

— 

7.58 

— 

— 

0.80 

9.43 

— 

1.78 

0.32 

2.43 

— 

100.00 

— 

Theory 

36.00 

10.48 

29.32 

2.00 

6.30 



2.10 

8.00 



3.10 



2.70 



100.00 



XXVI 

35.64 

9.93 

29.41 

2.90 

6.56 

1.10 

Trace 

1.65 

8.00 

— 

3.03 

0.16 

2.94 

— 

101.32 

— 

Theory 

35.85 

10.43 

30.47 



8.07 





2.09 

7.97 



1.54 



3.58 



100.00 



LXXI 

35.34 

10.45 

30.49 

— 

8.22 

0.40 

Trace 

2.32 

7.76 

Trace 

1.76 

0.15 

3.60 

— 

100.49 

2.88 

Theory 

35.23 

10.29 

30.02 



13.25 





0.69 

6.38 



2.28 



1.76 



100.00 



LXX 

26.29 

9.04 

30.44 

13.23 

— 

— 

1.02 

6.32 

— 

1.94-|-K20 

— 

1.72 

— 

100.00 

— 

Theory 

35.26 

11.12 

28.72 

0.88 





5.49 

14.69 

— 

0.76 

— 

3.08 

0.00 

100.00 

— 

XLVI 

35.26 

10.45 

28.79 

^^_ 

0.86 

0.65 

— 

5.09 

14.58 

Trace 

0.94 

0.18 

3.10 

0.78 

100.37 

— 

spar  Group. 

Felspar  group  conform  to  the  following  types 

D.  Si  •  R  •  Si  •  Si  •  R  •  Si  =  6  R202  •  22  SiO2, 

E.  SAi  •  R  •  Si  •  Si  -  R  •  Si  =  6  R203  •  24  Si02. 


or  the  general  formula 
m  MO  •  5  R90,  •  22  SiO 


2  •  n  H20. 


Analyst 

Si02 

A1208 

Fe20s 

FeO 

CaO 

MgO 

K8O 

Na20 

H,o 

Total 

Heddle 

Theory 
LXVI 

64.38 
64.54 

23.63 
24.04 

1.95 
2.31 

— 

1.37 
1.21 

0.97 
0.77 

2.29 
2.59 

4.53 
4.13 

0.88 
0.84 

100.00 

100.43 

Raimondi 

Theory 
XCV 

62.98 
63.20 

23.12 
24.00 

1.91 
1.50 

- 

4.68 
4.36 

0.95 
0.72 

Trace 

4.43 
4.20 

1.93 
1.90 

100.00 
99.88 

Deville 

Theory 
CIX 

63.32 
63.85 

24.43 
24.05 

z 

~ 

4.69 
5.04 

0.47 
0.38 

1.12 

0.88 

5.20 
5.04 

0.87 
0.76 

100.00 
100.00 

412 


THE   FELSPAR   GROUP 


Source 

4 

4  MO  •  5  A12O3  •  22  SiO2 

4  MO  =  2.25  Na20  •  1.25  CaO  •  0.5  K2O 

Oligoclase 

Mer  de  Glace 

5 

4MO-5R203-22Si02 

4  MO  =  2.25  Na2O  •  1.5  CaO  •  0.25  K2O 

» 

Rispond 

•1H20 

6 

4MO-5Al2O3-22Si02 

4  MO  =  2.5  Na2O  •  1  CaO  •  0.5  K2O 

» 

Vesuvius 

t 

»             »>             » 

t> 

»> 

Freiberg 

8 

»             »>             »» 

„ 

M 

Marienberg 

9 

4  MO  •  5  A12O3  •  22  SiO2 

M 

Arendal 

•1H20 

10 

4  MO  •  5  A12O3  •  22  SiO2 

4  MO  =  2.  75  Na2O  •  0.75  CaO  •  0.25  MgO 

„ 

Danviks 

•0.25K20 

|| 

Tulb 

11 

4  MO  •  5  B2O3  •  22  SiO2 

4  MO  =  2.75  Na2O  •  0.75  CaO  •  0.25  MgO 

ff 

Rottchen 

•0.25  K2O  ;  5  R2O3  =  4.75  A12O3-0.25  Fe2O3 

12 

4  MO  •  5  A12O3  •  22  SiO2 

4MO  =  3Na2O-lCaO 

» 

Ariege 

13 

»             »             » 

Culsagee, 

N.C. 

14 

5MO-5R2O3-22SiO2 

5  MO  =  1.75  Na2O  •  2.5  CaO  •  0.75  K2O 

>» 

Neurode 

5  R2O3  =  4.75  A12O3  •  0.25  Fe2O3 

15 

5MO-5Al203-22SiOa 

5  MO  =  2  Na2O  •  2  CaO  •  0.5  H2O-0.25  MgO 

M 

Aberdeen 

•0.25K20 

16 

>f             >»             »» 

5  MO  =  2  Na2O  •  2.5  CaO  •  0.5  K2O 

» 

Hierro 

17 

»             >»             »> 

5MO  =  2Na2O-3CaO 

„ 

Campo 

maior 

18 

»>             )»             » 

5  MO  =  2.25  Na2O  •  2.25  CaO    0.5  K2O 

y9 

Rosetown, 

N.J. 

19 

5  MO  •  5  A12O3  •  22  SiO2 

»             »             »             » 

ff 

Pytterlaks 

•1H2O 

20 

5  MO  •  5  A1203  •  22  SiO2 

„ 

Andesine 

Pikruki 

•1H20 

21 

5  MO  •  5  A12O3  •  22  SiO2 

5  MO  =  2.25  NaaO  •  2.5  CaO  •  0.25  K2O 

n 

Sardinia 

22 

5  MO  •  5  A12O3  •  22  SiO2 

5  MO  =  2.5  Na2O  •  1  CaO  •  0.75  FeO 

Oligoclase 

KjSrrestad 

•1H20 

•  0.5  H2O-  0.25  K2O 

23 

5  MO  •  5  A12O3  •  22  SiO2 

5  MO  =  2.5  Na2O  •  2  CaO  -  0.25  K2O 

t> 

Ditr6 

•1H20 

•0.25H20 

24 

5  MO  •  5  A12O3  •  22  SiO2 

5  MO  =  2.5  Na20  •  2  CaO  •  0.5  K2O 

M 

Com  j  os, 

Colorado 

25 

»»             »»             »» 

5  MO  =  2.5  Na20  •  2  CaO  •  0.5  H2O 

M 

Anna-See 

26 

>»             »             » 

5MO  =  2.5Na2O  •  2.25  CaO  •  0.25  K2O 

H 

M.  Mulatto 

27 

»t             »             » 

»              »               t>               » 

>» 

Knader 

28 

»>             >»             » 

5  MO  =  2.75  Na2O  •  1.5  CaO  •  0.5  MgO 

»> 

Chester, 

•0.25  H20 

Mass. 

THE   FELSPAR   GROUP 


413 


Analyst 

SiOa 

Al»0, 

Fe80, 

FeO 

CaO 

MgO 

K»O 

Na20 

Hao 

Total 

Delesse 

Theory 
LVII 

63.27 
63.25 

24.44 
23.92 

— 

z 

3.36 
3.23 

0.32 

2.25 
2.31 

6.68 
6.78 

— 

100.00 
99.91 

Heddle 

Theory 
XLIX 

62.15 
61.85 

21.61 
21.70 

3.77 
3.37 

0.20Mn2O3 

3.95 
4.13 

0.09 

1.11 
1.63 

6.57 
6.95 

0.85 
0.37 

100.00 
10U.29 

G.  v.  Rath 

Theory 
XLIX 

63.22 
62.36 

24.42 
23.38 





2.68 
2.88 

— 

2.35 
2.66 

7.43 
7.42 

0.13 

100.00 

98.83 

Kersten 

Theory 
VII 

63.22 
62.97 

24.42 
23.48 

0.51 

z 

2.68 
2.83 

0.24 

2.35 

2.42 

7.43 
7.22 

~ 

100.00 
99.69 

M 

Theory 
XXXIV 

63.22 
63.20 

24.42 
23.50 

0.31 

z 

2.68 
2.42 

0.25 

2.35 
2.22 

7.43 
7.42 

~ 

100.00 
99.32 

Dirvell 

Theory 
LXXVIII 

62.68 
63.53 

24.22 

24.05 

— 

z 

2.66 
2.60 

— 

2.33 
1.86 

7.36 

8.02 

0.85 
0.90 

100.00 
100.96 

Berzelius 

Theory 
XCII 

63.28 
63.70 

24.45 
23.95 

0.50 

z 

2.01 
2.05 

0.96 
0.65 

1.13 
1.20 

8.17 
8.11 

z 

100.00 
100.16 

Bothe 

Theory 
XVI 

63.14 
63.16 

23.18 
22.14 

1.92 
2.51 

— 

2.01 
2.07 

0.48 
0.65 

1.12 
1.34 

8.15 
8.13 

z 

100.00 
100.00 

Laurent 

Theory 
LIII 

63.70 
62.60 

24.62 
24.60 

— 

— 

2.70 
3.00 

0.20 

z 

8.98 
8.90 

z 

100.00 
99.40 

J.  L.  Smith 

Theory 

63.72 

24.61 

— 

— 

2.70 

— 

— 

8.97 



100.00 

CXXXII 

64.12 

24.20 

0.14 

— 

2.80 

— 

— 

9.28 

— 

100.54 

Konig 

Theory 
II 

61.00 
61.54 

22.40 
22.36 

1.85 
1.75 

z 

6.47 
6.23 

~ 

3.26 

2.82 

5.02 
4.91 

z 

100.00 
99.61 

Heddle 

Theory 
LXX 

62.61 
62.53 

24.19 
23.52 

1.28 

— 

5.31 
4.97 

0.47 
0.37 

1.11 
1.32 

5.88 
6.19 

0.43 
0.60 

100.00 
100.78 

Schnorf 

Theory 
CLIII 

61.66 
60.99 

23.82 
23.98 

0.90 

z 

6.54 
6.46 

. 

2.19 

2.08 

5.79 
5.44 

z 

100.00 
99.85 

Merian 

Theory 
LII 

62.20 
61.81 

24.04 
24.45 

~ 

z 

7.92 
8.04 

0.34 

0.59 

5.84 
6.19 

z 

100.00 
101.42 

Kemp 

Theory 
CXXXIV 

61.61 
61.12 

23.81 
23.90 

~ 

z 

5.88 
5.80 

z 

2.19 
2.58 

6.51 

6.78 

~ 

100.00 
100.18 

Struve 

Theory 

cm 

61.09 
60.90 

23.60 
24.32 

~ 

— 

5.83 
5.78 

— 

2.20 
1.87 

6.46 
6.51 

0.82 
0.62 

100.00 
100.00 

n 

Theory 
LXXXIII 

61.10 
60.90 

23.60 
24.32 

~ 

z 

5.83 
5.78 

z 

2.18 
1.87 

6.46 
6.51 

0.83 
0.62 

100.00 
100.00 

Dupare 

Theory 
LIV 

61.88 
62.65 

23.91 
24.19 

~ 

z 

6.56 
6.28 

z 

1.11 
1.24 

6.54 
6.48 

— 

100.00 
100.84 

Dirvell 

Theory 

XC 

61.50 
61.80 

23.77 
25.11 

— 

2.52 
2.50 

2.60 
2.38 

z 

1.09 
0.97 

7.22 
7.18 

1.30 
1.60 

100.00 
101.54 

Fellner 

Theory 
XXXVI 

61.60 
61.68 

23.80 
23.95 

- 

z 

5.23 
5.35 

— 

1.10 
1.09 

7.22 
6.99 

1.05 
1.05 

100.00 
100.27 

G.  v.  Rath 

Theory 
CXXVIII 

61.57 

61.88 

23.79 
24.18 

- 

z 

5.22 

4.79 



2.19 
2.50 

7.23 
6.95 



100.00 
100.30 

»> 

Theory 
XXXVII 

62.68 
63.05 

24.32 
23.61 

— 

— 

5.31 
5.28 

— 

— 

7.36 

7.82 

0.43 
0.24 

100.00 
100.00 

Petersen 

Theory 
XLI 

61.84 
62.84 

23.89 
23.53 

— 

- 

5.91 
5.50 

- 

1.10 
1.15 

7.26 
7.65 

z 

100.00 
100.67 

Haughton 

Theory 
LXIV 

61.84 
62.40 

23.89 
23.60 

- 

- 

5.91 
5.62 

— 

1.10 
1.66 

7.26 
7.04 

___ 

100.00 
100.40 

Jackson 

Theory 
CXLIII 

62.05 
62.00 

23.98 
24.40 

— 

— 

3.95 
3.50 

0.94 
0.70 

_ 

8.02 
8.07 

1.06 
1.00 

100.00 
99.67 

414 


THE   FELSPAR   GROUP 


Source 

29 

5  MO 

•  5  A12O3 

•  22  Si02 

5  MO  =  2.75  Na2O  •  1.5  CaO-0.5K2O-0.25H2O 

Oligoclase 

Monnoir, 

Canada 

30 

5  MO 

•  5  R203 

•  22  Si02 

5  MO  =  2.75  Na2O-1.5  CaO-0.5  H2O-0.25  K2O 

" 

Cragie 

31 

5  MO 

•  5  A12O3 

•  22  Si02 

5  MO  =  2.75  Na2O-1.5  CaO-0.5H2O-0.25  MgO 

Chester, 

•1H20 

Mass. 

32 

5  MO 

•  5  A1203 

•  22  Si02 

5  MO  =  2.75  Na2O-1.5  CaO-0.5  FeO-0.25  K2O 

M 

Kyffhauser 

•1H20 

33 

5  MO 

•  5  A1203 

•  22  Si02 

5  M0  =  2.75  Na20  •  1.75  CaO  •  0.25  MgO 

M 

Moland, 

•   1  H20 

-  0.25  K2O 

Arendal 

34 

5  MO 

•  5  A1203 

•  22  Si02 

5  MO  =  2.75  Na2O  •  1.75  CaO  •  0.25  FeO 

N 

Arendal 

•  0.25  K20 

35 

5  MO 

•  5  A1203 

•  22  Si02 

5  M0  =  2.75  Na2O  •  2  CaO  •  0.25  K2O 

n 

•1H20 

36 

5  MO 

•  5  A1203 

•  22  Si02 

„ 

» 

Rhiconieh 

37 

„ 

Fredriks- 

varn 

88 

M 

- 

» 

5  MO  =  2.75  Na2O  •  2.25  CaO 

» 

Alausi 

39 

M 

» 

N 

5  MO  =  3  Na2O  •  0.5  CaO  •  1.5  K2O 

m 

Ditro 

40 

M 

» 

» 

5  MO  =  3  Na20  •  2.75  CaO  •  0.25  K2O 

» 

Tvedestrand 

41 

» 

» 

» 

,r~ 

H 

Orenburg 

42 

M 

„ 

» 

5MO  =  3Na2O  •  2  CaO 

M 

Perlenhardt 

43 

M 

M 

„ 

M 

» 

Itterby 

44 

» 

» 

M 

5  MO  =  3.25  Na2O  •  1.25  CaO  •  0.5  MgO 

n 

H 

45 

>f 

tf 

f> 

5  MO  =  3.25  Na2O  •  1.75  CaO 

n 

JestreKjorre- 

stadb.Bamle 

46 

M 

M 

>? 

»                 »                 » 

n 

Cragie 

Bukler 

47 

6  MO 

•  5  R2O3 
•1H20 

22  Si02 

6  MO  =  2  NaaO-2.25  CaO-1  MgO-0.75  K2O 
5  R2O3  =  4.5  A12O3  •  0.5  Fe2O3 

» 

Jamaica- 
Mts.  Can. 

48 

6  MO 

•  5  A12O3 

•  22  Si02 

6  MO  =  2.25  Na2O-3  CaO-0.5  MgO-0.25  K2O 

9t 

Santorine 

49 

6  MO 

•  5  R2O3 

22  SiO8 

6  MO  =  2.5  Na2O  •  1.5  CaO  •  1  K2O  •  0.5  MgO 

Buxburn 

•1H20 

•  0.5  H2O  ;  5  R2O3=4.75  A12O3  •  0.25  Fe2O3 

50 

6  MO 

•  5  A12O3 

•  22  Si02 

6  MO  =  2.5  Na2O  •  2.25  CaO-1  MgO-0.25  K2O 

ft 

Gebel 

•2H20 

Duchan 

THE   FELSPAR   GROUP 


415 


Analyst 

Si02 

A120, 

Fe203 

FeO 

CaO 

MgO 

K,0 

Na,0 

H,0 

Total 

Hoffmann 

Theory 

61.29 

23.68 

—  , 

— 

3.90 

— 

2.18 

7.91 

1.04 

100.00 

CXLIV 

62.05 

22.60 

— 

— 

3.96 

— 

1.80 

7.95 

0.80 

99.91 

Heddle 

Theory 

61.93 

22.73 

— 

— 

3.94 

— 

1.10 

8.00 

0.42 

100.00 

LXXI 

61.58 

22.00 

— 

— 

4.19 

— 

1.52 

8.27 

0.54 

99.66 

Jackson 

Theory 

62.05 

23.98 



— 

3.95 

0.94 



8.02 

1.06 

100.00 

CXLIII 

62.03 

24.40 

— 

— 

3.50 

0.70 

— 

8.07 

1.00 

99.67 

Streng 

Theory 

61.11 

23.61 

— 

1.66 

3.89 

— 

1.09 

7.80 

0.84 

100.00 

XII 

60.94 

24.22 

— 

1.66 

3.94 

— 

0.95 

7.65 

0.79 

100.15 

Dirvell 

Theory 

61.39 

23.72 





4.56 

0.46 

1.09 

7.93 

0.85 

100.00 

LXXXIII 

61.84 

24.77 

— 

— 

4.20 

0.30 

0.88 

8.14 

0.50 

100.63 

Theory 

62.68 

24.22 





2.66 



2.33 

7.36 

0.85 

100.00 

LXXVII 

63.53 

24.05 

— 

— 

2.60 

— 

1.86 

8.02 

0.90 

100.96 

Konig 

Theory 

61.28 

23.68 



— 

5.19 

— 

1.09 

7.91 

0.85 

100.00 

CXIV 

60.69 

24.24 

0.71 

— 

4.63 

— 

1.28 

7.75 

0.85 

100.15 

Haughton 

Theory 

61.81 

23.87 

— 

— 

5.24 

— 

1.10 

7.98 

— 

100.00 

LXXV 

61.88 

24.80 

— 

— 

4.93 

— 

0.98 

8.12 

— 

100.71 

Pisani 

Theory 

61.81 

23.87 

— 

— 

5.24 

— 

1.10 

7.98 

— 

100.00 

LXXXVII 

62.25 

24.80 

0.25 

— 

4.90 

— 

0.80 

7.80 

0.20 

101.00 

Siemiradzki 

Theory 

62.08 

23.98 





5.92 



, 

8.02 

.  

100.00 

CXXIV 

61.58 

25.30 

— 

— 

6.08 

— 

— 

8.14 

— 

101.10 

Fellner 

Theory 

59.43 

22.97 

— 

— 

1.96 

— 

6.35 

8.37 

1.62 

100.00 

XXXV 

60.28 

22.40 

— 

— 

1.17 

0.09 

6.37 

8.44 

1.61 

100.36 

Scheerer 

Theory 

61.75 

23.86 





4.58 



1.10 

8.71 



100.00 

LXXXVI 

61.30 

23.77 

0.36 

— 

4.78 

— 

1.29 

8.50 

— 

100.00 

G.  v.  Rath 

Theory 

61.75 

23.86 





4.58 



1.10 

8.71 



100.00 

CXVII 

60.34 

24.39 

0.18 

— 

5.56 

— 

0.73 

8.44 

0.33 

99.97 

Theory 

62.04 

23.96 



— 

5.26 

— 

— 

8.74 

— 

100.00 

XV 

62.18 

23.52 

— 

— 

5.33 

— 

— 

8.97 

— 

100.00 

Jannetaz 

Theory 

62.04 

23.96 

— 

— 

5.26 

— 

— 

8.74 

— 

100.00 

XCV 

63.19 

23.52 

— 

— 

4.81 

— 

— 

9.01 

— 

100.53 

Berzelius 

Theory 

62.23 

24.04 





3.29 

0.94 



9.50 



100.00 

XCIII 

61.55 

23.80 

— 

— 

3.18 

0.80 

0.38 

9.67 

— 

99.38 

G.  v.  Rath 

Theory 

61.98 

23.95 

— 

— 

4.61 

— 

— 

9.46 

— 

100.00 

LXXXIX 

61.91 

23.68 

— 

— 

4.45 

— 

— 

9.64 

— 

100.00 

Haughton 

Theory 

61.98 

23.95 

— 

— 

4.61 

— 

— 

9.46 

— 

100.00 

LXXII 

62.00 

23.20 

—  • 

— 

4.71 

— 

— 

9.20 

— 

100.00 

Hunt 

Theory 

59.26 

20.16 

3.59 



5.66 

1.80 

3.16 

5.57 

0.80 

100.00 

CXLVII 

58.60 

21.10 

2.88 

— 

5.40 

1.84 

3.08 

5.51 

0.80 

99.21 

Fouque 

Theory 

60.52 

23.39 



— 

7.71 

0.92 

1.07 

6.39 

— 

100.00 

LI 

59.70 

23.20 

0.40 

— 

7.90 

1.00 

0.80 

6.60 

— 

99.60 

Heddle 

Theory 

59.34 

21.78 

1.80 



3.77 

0.90 

4.23 

6.97 

1.21 

100.00 

LXIX 

59.53 

21.05 

1.81 

— 

3.63 

0.88 

4.73 

7.23 

1.88 

100.74 

Delease 

Theory 

59.71 

23.07 





5.70 

1.81 

1.06 

7.01 

1.64 

100.00 

CXLVIII 

58.92 

22.49 

0.75 

0.60MnO 

5.53 

1.87 

0.93 

6.93 

1.64 

99.60 

416 


THE   FELSPAR  GROUP 


B. 
sVR-Si-Si-R- 


Felspars  of  the  type 
Si  =  5  R203  •  24  Si02 


Source 

51 

4  MO  •  6  A12O3  •  24  SiO2 

4MO  =  2.25Na20  •  0.5  CaO  •  0.75  K2O 

Oligoclase 

Lessines 

•1H20 

•0.5  MgO 

62 

4MO-5R203-24Si02 

4  MO  =  2.75  Na20  -  0.75  CaO  -  0.5  K2O 

M 

Old  Meldrum 

63 

5MO-5Al203-24SiO2 

5MO  =  2.25Na2O    2.5  CaO  •  0.25  K2O 

;» 

Furth 

64 

» 

5  MO  =  2.5  Na2O  •  1  CaO  •  1  K2O  •  0.5  MgO 

M 

Hartenberg 

55 

,» 

5  MO  =  2.5  Na2O  •  1.5  CaO  •  0.75  H2O 

m 

Visembach 

•0.25K20 

56 

,,                          „                          „ 

5  MO  =  2.5  Na2O  •  1.5  CaO  •  1  K2O 

,t 

Pierrepont, 

N.S. 

57 

„ 

5  MO  =  2.75  Na2O-0.75  CaO-1  K2O-0.5  MgO 

?> 

Ajatskaja 

5  R2O3=4.5  A12O3  •  0.5  Fe2O3 

58 

5MO-5R2O3    24Si02 

5  MO  =  2.75  Na2O  •  1.5  CaO  •  0.5  H2O 

M 

Coyle, 

•0.25K20 

Aberdeen 

59 

5MO-5Al2O3-24Si02 

5  MO  =  3  Na2O  -  0.75  CaO-1  K2O-0.25  MgO 

n 

Pico  de 

Teneriffe 

60 

„ 

„ 

M 

» 

61 

5  MO  •  5  A12O3  •  24  SiO2 
•1H20 

5  MO-3  Na2O  •  1  CaO  •  0.5  K2O  •  0.5  H2O 

" 

Badenweiler 

62 

5  MO  •  5  A12O3  .  24  SiO2 

5  MO  =  3  Na2O  •  1.5  CaO  •  0.5  K2O 

»' 

Wittichen 

63 

»>           »           »> 

„ 

M 

Gaggenau 

64 

»           .•>           »> 

5  MO  =  3.25  Na2O  •  1  MgO  •  0.75  K2O 

» 

Laacher  See 

65 

„ 

5MO  =  3.25Na20    1.25  CaO  •  0.25  MgO 

n 

Coromandel 

•  0.25  K20 

66 

5MO-5Al2O8'24SiO2 

5  MO  =  3.25  Na2O  -1.5  CaO  •  0.25  K2O 

n 

Veltlin 

67 

» 

» 

Niedermendig 

68 

» 

» 

M 

Itterby 

69 

„ 

„ 

,- 

(Granite) 

70 

» 

» 

M 

Lairg 

71 

5  MO  •  5  A12O3  •  24  SiO2 

5  MO  =  3.5  Na2O  •  0.5  CaO  •  0.75  K2O 

Pico  de 

•  0.25  MgO 

Teneriffe 

72 

„ 

5  MO  =  3.5  Na2O  •  0.75  CaO  •  0.5  K2O 

n 

Arendal 

•0.25  MgO 

73 

„ 

5  MO  =  3.5  Na2O  •  0.75  CaO  •  0.75  K2O 

" 

Boden 

74 

» 

5  MO  =  3.5  Na2O  •  1.25  CaO  •  0.25  K2O 

n 

Danbury, 

Conn. 

THE   FELSPAR   GROUP 


417 


or  the  general  formula 
mMO  •  5R90,  •  24S10. 


n  H90. 


Analyst 

|     SiOs 

Al,0, 

Fe,0, 

FeO 

CaO 

MgO 

K,O 

NajO 

H,0 

Total 

Delesse 

Theory 
LXI 

64.66 
63.70 

22.91 
22.64 

0.53 

— 

1.28 
1.44 

0.90 
1.20 

3.17 
2.81 

6.27 
6.15 

0.81 
1.22 

100.00 
99.69 

Heddle 

Theory 
LXVIII 

64.75 
64.67 

21.78 
22.18 

1.80 
1.44 

z 

1.89 
1.89 

0.02 

2.11 
1.54 

7.67 
7.64 

0.15 

100.00 
99.53 

v.  Giimbel 

Theory 
XXXI 

63.92 
64.40 

22.64 
23.07 

z 

0.27 

6.21 
5.61 

— 

1.04 
0.96 

6.19 

5.85 

— 

100.00 
100.16 

G.  v.  Rath 

Theory 
XIV 

63.30 
63.50 

22.42 
21.81 

0.66 

~ 

2.46 
2.32 

0.88 
0.95 

4.13 
3.65 

6.81 
6.84 

— 

100.00 
99.81 

Delesse 

Theory 
XXIII 

64.69 
63.88 

22.91 

22.27 

— 



3.77 
3.45 



1.06 
1.21 

6.96 
6.66 

0.61 
0.70 

100.00 
98.68 

Penfield  and 
Sperry 

Theory 
CXL 

63.08 
63.76 

22.34 
22.67 

0.41 



3.68 
3.05 



4.12 
3.60 

6.78 
6.89 

0.40 

100.00 
100.78 

Francis 

Theory 
CXI 

62.45 
61.06 

19.92 
19.68 

3.48 
4.11 



1.82 
2.16 

0.87 
1.05 

4.07 
3.91 

7.39 
7.55 

- 

100.00 
99.52 

Heddle 

Theory 
LXVII 

63.95 
63.54 

21.54 
21.45 

1.78 
1.86 



3.73 

3.88 

0.23 

1.04 
1.07 

7.57 
7.64 

0.39 
0.44 

100.00 
100.11 

Delesse 

Theory 
CXLIX 

63.11 

62.97 

22.35 
22.29 

— 



1.84 
2.06 

0.44 
0.54 

4.11 
3.69 

8.15 
8.45 

— 

100.00 
100.00 

»> 

Theory 
CL 

63.11 
62.54 

22.35 
22.49 

— 



1.84 
2.18 

0.44 
0.41 

4.11 
4.54 

8.15 

7.84 

— 

100.00 
100.00 

Wollemann 

Theory 
XXIV 

63.55 
63.22 

22.51 
22.95 

— 



2.47 
2.50 

~ 

2.07 
1.93 

8.21 
8.12 

1.19 
1.36 

100.00 
100.35 

Hebenstreit 

Theory 
XXV 

63.52 
62.90 

22.50 
22.23 

— 



3.71 
4.45 

~ 

2.07 
2.09 

8.20 
8.48 

— 

100.00 
100.15 

Seneca 

Theory 
XXVIII 

63.52 
63.63 

22.50 
22.52 

— 



3.71 
3.85 

0.44 

2.07 
2.29 

8.20 
8.39 

- 

100.00 
100.12 

Fouque 

Theory 
XIX 

63.66 
63.50 

22.55 
22.10 

— 



0.30 

1.77 
1.80 

3.11 
3.40 

8.91 
8.90 

— 

100.00 
100.00 

Pisani 

Theory 
CXXI 

63.86 
64.00 

22.63 
23.50 

— 



3.10 

2.72 

0.44 
0.60 

1.04 
0.77 

8.93 
9.00 

0.16 

100.00 
100.75 

G.  v.  Rath 

Theory 
XLVI 

63.74 
64.58 

22.58 
23.08 

— 



3.72 

3.49 

~ 

1.04 
0.62 

8.92 
8.98 

— 

100.00 
100.75 

»> 

Theory 
XVII 

63.74 
63.06 

22.58 
23.27 

— 



3.72 
4.16 

~ 

1.04 
0.62 

8.92 
8.93 



100.00 
100.04 

Lemberg 

Theory 
XCIX 

63.74 
63.38 

22.58 
22.98 

— 



3.72 
3.62 

~ 

1.04 
0.55 

8.92 
9.10 

0.37 

100.00 
100.00 

G.  v.  Rath 

Theory 
CXIII 

63.74 
63.83 

22.58 
22.58 

— 

— 

3.72 
3.42 

— 

1.04 
1.02 

8.92 
8.86 

— 

100.00 
100.15 

Heddle 

Theory 
LXXIII 

63.74 
62.81 

22.58 
22.92 

0.16 



3.72 
4.25 

0.08 

1.04 

0.84 

8.92 
8.53 

0.29 

100.00 
99.88 

Delesse 

Theory 
CLI 

63.28 
63.81 

22.43 

21.98 

— 



1.23 
1.10 

0.44 
0.66 

3.09 
2.99 

9.54 
9.46 

— 

100.00 
100.00 

Hagen 

Theory 
LXXVI 

63.56 
63.51 

22.51 
23.09 

— 



1.85 

2.44 

0.44 
0.77 

2.07 
2.19 

9.57 
9.37 



100.00 
101.37 

Kerndt 

Theory 
IV 

63.17 
61.66 

22.38 
22.56 

0.35 

0.40  MnO 

1.84 
2.02 

0.10 

3.09 

3.08 

9.52 
9.43 

~ 

100.00 
100.00 

Smith  and 
Brush 

Theory 
CXLI 

63.71 
63.76 

22.56 
22.56 

— 

z 

3.09 
3.09 

z 

1.04 
0.55 

9.60 
9.72 

0.26 

100.00 
99.94 

2    E 


418 


THE   FELSPAR   GROUP 


Source 

75 

5  MO  •  5  AljjO,  •  24  SiO2 

5MO  =  3.5Na2O    1.25  CaO    0.25K2O 

Oligoclase 

Telemarken 

76 

5  MO  •  5  A12O3  •  24  SiO2 
•1H20 

5  MO  =  3.5  Na2O  •  1.5  CaO 

» 

Srnin 

77 

5  MO  •  5  A12O3  •  24  SiO2 

5  MO  =  4  Na2O  •  0.75  CaO  •  0.25  K2O 

M 

Turin 

78 

6  MO  •  5  A12O3  •  24  SiO2 

6  MO  =  2.  75  Na2O  •  2.25  CaO  •  0.5  FeO 

Kyffhauser 

•0.25MgO-0.25K2O 

79 

» 

6  MO  =  3.25  Na20  •  2.75  CaO 

- 

Alagnon 

80 

»           »           » 

6MO  =  4Na2O-2CaO 

» 

Pargas 

C.  Felspars  of  the  type 

Si  •  R  •  Si  •  Si  •  R  •  Si  =  6  R203  •  20  Si02 

Source 

81 

5MO-6Alo03-20SiO2 

5  MO  =  1.75  Na2O-2.75  CaO  •  0.25  MgO 

Andesine 

St.  Raphael  in 

•  1  H2"0 

•  0.25  H2O 

Esterelgebirge 

bei  Trejus 

82 

5MO-6Al203-20SiO2 

5  MO  =  2  Na.O  •  2.75  CaO  •  0.25  K2O 

M 

Dubnick 

•4H20 

83 

5MO-6Al203-20SiO2 

5MO  =  2Na2O-3CaO 

M 

Adamelle- 

Gebirge 

84 

5  MO  •  6  R2O3  •  20  SiO2 

5  MO  =  2.25  Na2O-2.5  CaO-0.25  MgO 

» 

Descaberado 

6  R2O3  =  5.5  A12O3  •  0.5  Fe2O3 

Chico 

85 

6  MO  •  6  A12O3  •  20  SiO2 

6MO=4.75CaO-1.25FeO 

Labradorite 

Silicite,  Antrim 

•1H20 

86 

6  MO  •  6  A12O3  •  20  SiO2 

6MO  =  1.25Na20-3.25CaO-0.75K2O 

,, 

Lakonien 

•3H20 

•0.5MgO-0.25H2O 

87 

6MO-6R2Oa-20SiO2 

6  MO  =  1.25  Na2O  •  4  CaO  •  0.5  MgO 

tt 

Nicolosi 

•0.25  K2O  ;  6  R2O3=5.5  A12O3-0.5  Fe2O3 

88 

99                        99                        99 

6  MO  =  1.25  Na2O  •  4.25  CaO  •  0.5  H2O 

n 

Kiew 

6  R2O3=5.75  A12O3  •  0.25  Fe2O3 

89 

6  MO  •  6  A12O3  •  20  SiO2 

6  MO  =  1.25  Na2O  •  4.25  CaO  •  0.5  K2O 

Andesine 

Tunguragua 

90 

6MO-6R2O3-20Si02 

6  MO  =  1.25  Na2O  •  4.5  CaO  •  0.25  MgO 

Labradorite 

Lhama 

6  R2O3=5.75  A1203  •  0.25  Fe2O3 

91 

6  MO  •  6  A12O3  •  20  SiO2 

6MO  =  1.5Na20  •  3.5  CaO  •  0.75  FeO 

Andesine 

Recsk  b.  Erlau 

•2H20 

•0.25K2O 

92 

6MO-6Al2O3--20SiO2 

6  MO  =  1.5  Na2O  •  4.5  CaO 

» 

Muretto  Pass 

93 

6MO-6Al2O3-20SiO2 
•2H20 

6  MO  =  1.75  Na2O  •  3  CaO  •  0.75  K2O 
•0.25MgO-0.25H2O 

» 

Odenwald 

94 

6MO-6Al203-20Si02 

6  MO  =  1.75  Na2O  •  3.25  CaO  •  0.75  H2O 

» 

Oberstein 

•3H20 

•0.25K20 

95 

6MO-6R2O3-20Si02 

6  MO  =  1.75  Na2O  •  3.5  CaO  •  0.5  H2O 

»> 

ChateauRicher, 

•0.25  K2O;  6  R2O3=5.75A12O3-0.25  Fe2O3 

Canada 

96 

6  MO  •  6  A12O3  •  20  SiO2 

6  MO  =  1.75  Na2O  •  4  CaO  •  0.25  K2O 

>» 

Le  Prese 

97 

99 

Hohe  Wald, 

Odenwald 

THE   FELSPAR   GROUP 


419 


Analyst 

SiO, 

A120, 

Fe,0, 

FeO 

CaO 

MgO 

K,0 

Na,0 

H,o 

Total 

Pisani 

Theory 
LXXXVIII 

63.71 
65.30 

22.56 
23.00 

— 

— 

3.09 
2.42 

z 

1.04 
0.70 

9.60 
9.65 

0.20 

100.00 
101.27 

C.  v.  Hauer 

Theory 
XXXIII 

63.46 
63.16 

22.49 
23.16 

z 

— 

3.70 
3.00 

~ 

0.17 

9.56 
9.72 

0.79 
0.79 

100.00 
100.00 

Rocholl 

Theory 
XLVII 

63.62 
62.52 

22.53 
22.40 

- 



1.85 
2.29 

~ 

1.04 
1.19 

10.96 
10.78 

— 

100.00 
99.18 

Streng 

Theory 
XI 

60.76 
60.01 

21.52 
21.66 

- 

~ 

5.32 
5.15 

0.42 
0.68 

0.99 
1.37 

7.19 
7.06 

2.28 
2.59 

100.00 
100.08 

Fouque 

Theory 
LIX 

62.46 
62.40 

22.12 

22.80 

- 

~ 

6.68 
7.00 

~ 

0.50 

8.74 
8.40 

— 

100.00 
101.10 

Bonsdorff 

Theory 
CI 

62.34 
62.03 

22.08 
21.34 

1.00 

~ 

4.84 
4.86 

z 

— 

10.74 
10.77 

— 

100.00 
100.00 

or  the  general  formula 

m  MO  •  6  R203  •  20  Si02  •  n  H20. 


Analyst 

Si02 

Al,03 

Fe,0, 

FeO 

CaO 

MgO 

K,0 

Na80 

HaO 

Total 

Deville 

Theory 

56.96 

29-04 

— 

— 

7.31 

0-47 



5.15 

1.07 

100.00 

LVII 

57.01 

28.05 

— 

— 

7.53 

0.39 

0.12 

5.47 

1.43 

100.00 

K.  v.  Hauer 

Theory 

54.91 

28.00 

__ 



7.05 



1.08 

5.67 

^_ 

100.00 

XXXVII 

55.61 

28.64 

— 

— 

7.00 

— 

1.55 

5.59 

— 

101.63 

Val.  San 

Theory 

57.04 

29.09 



— 

7.98 





5.89 



100.00 

Valentino 

XLIX 

56.79 

28.48 

— 

— 

8.56 

— 

0.34 

6.10 

0.24 

100.51 

Domeyko 

Theory 

56.33 

26.33 

3.75 

— 

6.57 

0.47 

— 

6.55 

— 

100.00 

XCII 

55.30 

26.50 

4.30 

— 

6.20 

0.60 

— 

6.70 

— 

99.60 

Thomson 

Theory 

54.90 

28.00 

— 

4.12 

12.17 

— 

— 

— 

0.81 

100.00 

LXXVI 

54.80 

28.40 

— 

4.00 

12.40 

— 

— 

— 

0.60 

100.20 

Delesse 

Theory 

54.04 

27.56 

— 

— 

8.19 

0.90 

3.18 

3.49 

2.64 

100.00 

CXXI 

53.20 

27.31 

1.03 

— 

8.02 

1.01 

3.40 

3.52 

2.51 

100.00 

S.  v.  Walters- 

Theory 

54.90 

25.66 

3.66 

— 

10.25 

0.91 

1.08 

3.54 

— 

100.00 

hausen 

LXXI 

55.83 

25.31 

3.63 

— 

10.49 

0.74 

0.83 

3.52 

— 

100.35 

Segeth 

Theory 

55.79 

27.27 

1.86 

— 

11.07 



— 

3.60 

0.41 

100.00 

CXVIII 

55.49 

26.83 

1.60 

— 

10.93 

0.15 

0.36 

3.96 

0.51 

99.83 

Siemiradzki 

Theory 

55.19 

28.14 





10.95 



2.16 

3.56 



100.00 

cm 

54.89 

28.97 

— 

— 

10.28 

— 

1.72 

3.61 

— 

99.47 

Koto 

Theory 

55.41 

27.07 

1.85 



11.63 

0.46 

— 

3.58 

— 

100.00 

CXXVIII 

55.97 

27.60 

1.68 

— 

11.88 

0.66 

0.08 

3.83 

— 

101.70 

K.  v.  Hauer 

Theory 

54.19 

27.63 



2.43 

8.85 



1.06 

4.20 

1.64 

100.00 

XXXVI 

53.99 

26.78 

— 

2.22 

9.09 

0.30 

0.82 

4.21 

1.90 

99.31 

Mattirolo 

Theory 

55.63 

28.37 





11.68 



— 

4.32 

— 

100.00 

LII 

55.53 

28.38 

— 

— 

11.72 

— 

— 

4.13 

0.24 

100.00 

Behr 

Theory 

54.32 

27.70 





7.60 

0.45 

3.19 

4.91 

1.83 

100.00 

XIX 

54.70 

27.49 

0.55 

— 

7.64 

0.42 

2.76 

4.64 

1.65 

99.85 

Delesae 

Theory 

54.71 

27.90 



— 

8.30 

— 

1.07 

4.94 

3.08 

100.00 

XI 

53.89 

27.66 

0.97 

— 

8.28 

— 

1.28 

4.92 

3.00 

100.00 

Hunt 

Theory 

55.47 

27.11 

1.85 

— 

9.06 

— 

1.08 

5.01 

0.42 

100.00 

CXXII 

55.80 

26.90 

1.53 

— 

9.01 

0.27 

0.86 

4.77 

0.45 

99.59 

G.  v.  Rath 

Theory 

55.36 

28.23 





10.33 



1.08 

5.00 

— 

100.00 

LI 

55.15 

29.15 

— 

— 

9.90 

— 

0.80 

5.23 

— 

100.23 

Swiatkowski 

Theory 

55.36 

28.23 



— 

10.33 

— 

1.08 

5.00 

— 

100.00 

XVIII 

55.24 

29.02 

— 

— 

9.91 

0.19 

1.31 

5.13 

— 

100.80 

420 


THE  FELSPAR   GROUP 


Source 

98 

6MO-6A1203 

•  20  SiO2 

6  M0  =  1.75  Na20  -  4  CaO  •  0.25  K2O 

Labrador!  te 

Labrador 

99 

»                          5J 

»» 

»>             »             *»            }> 

» 

»» 

100 

J>                          ?> 

it 

j»                       it                       »                       »» 

n 

Campsie 

101 

„ 

»» 

>»                       »                       »                       » 

» 

Schriesheim 

102 

„ 

»i 

6  MO  =  1.75  Na2O  •  4  CaO  •  0.25  H2O 

" 

Suligata 

103 

„ 

w 

»»             »             »>             »» 

>» 

Nagyag 

104 
105 

»                          5J 

» 

„ 

» 

Piatra 
Poienitia 

Palma 

106 

JJ                          » 

M 

»             >»             »             » 

,, 

Rotundo 

107 

„ 

pi 

»             >»             »>             » 

H 

Kisbanya 

108 

J>                          » 

n 

6  MO  =  1.75  Na2O  •  4.25  CaO 

Andesine 

Pomasque 

109 

>5                          >J 

5> 

6  MO  =  2  Na2O  •  3.  75  CaO  •  0.  25  K2O 

5> 

Langlangchi 

110 

6  MO  •  6  R2O8  • 

20SiO2 

6  MO  =  2  Na20  •  3.75  CaO  •  0.25  MgO 
6  R2O3=5.25  A12O3  •  0.75  Fe2O3 

Labradorite 

Baumholder 

111 

7  MO  •  6  A12OS 

•  20  SiO2 

7  M0  =  0.5  Na20  •  3.75  CaO  •  1.75  K2O 
•  0.75  H20-  0.25  MgO 

" 

Labrador 

112 

7  MO  •  6  R2O3  • 

20  SiO2 

7  MO  =  1.5  Na20-3.75  CaO-1  MgO-0.5H20 
0.25  MnO;6  R2O3=5.75  A12O8-0.25  Fe2O3 

>? 

Val  del  Bove 

113 

7  MO  •  6  R2O3  • 
•1H2O 

20  SiO2 

7MO-1.5Na20-4CaO-lMgO-0.25  MnO 
•0.25H2O  ;  6R2O3=5.75Al2O3-0.25Fe2O3 

>• 

Etna 

114 

7MO-6R2O3- 
•1H20 

20  SiO2 

7  MO  =  1.5  Na20  •  4.75  CaO  •  0.25  MgO 
-  0.25  K20-  0.25  H2O 

» 

Mascali 

115 

7MO-6A1203 
•1H2O 

•20  SiO2 

7  MO  =  1.5  Na2O  •  4.75  CaO  •  0.5  MgO 
•  0.25  K2O 

» 

Montarville 

116 

7MO-6A1203 
•2H2O 

•  20  SiO2 

7MO  =  1.75Na20  •  3  CaO  •  0.75  H2O 
•  0.75  FeO  •  0.5  MgO  -  0.25  K2O 

Andesine 

Ilfeld 

117 

7  MO  •  6  A12O3 

•  20  SiO2 

7MO  =  1.75Na20  •  4.5  CaO  •  0.5  FeO 
•0.25K2O 

Labradorite 

Labrador 

118 

»           »' 

H 

7  MO  =  2  Na2O  •  4.25  CaO  •  0.5  H2O 
•0.25K20 

» 

Monte  Amiata 

119 

»>           j> 

» 

7MO  =  2Na2O-5CaO 

» 

Geschiebe  bei 
Berlin 

120 

7MO-6A1203 
•1H2O 

•  20  Si02 

7  MO  =  2.25  Na2O  •  3.75  CaO  •  0.5  H2O 
•0.5K20 

Andesine 

Illowa 

121 

7MO-6A1203 

•  20  Si02 

7  MO  =  2.25  Na2O  •  3.75  CaO  •  0.75  H2O 
•0.25K2O 

>» 

Rawdon 

122 

8  MO  •  6  R2O3  • 

20  SiO2 

8  MO  =  2.75  Na2O  •  5.25  CaO 

>» 

Los 
Pescadores 

THE  FELSPAR   GROUP 


421 


Analyst 

|     SiO, 

A1.0, 

Fe,0s 

FeO 

CaO 

MgO 

K,0   |  NaaO 

HaO 

Total 

Tschermak 

Theory 
CLII 

55.35 
56.00 

28.23 
27.50 

0.70 

z 

10.33 
10.10 

0.10 

1.08 
0.40 

5.01 
5.00 

— 

100.00 
99.80 

Klement 

Theory 
CLIII 

55.35 
56.10 

28.23 
27.33 

1.38 

— 

10.33 
10.33 

~ 

1.08 
0.36 

5.01 
5.17 

— 

100.00 
100.75 

Lehunt 

Theory 
LXXXIX 

55.35 
54.67 

28.23 

27.89 

0.31 

0.18  MnO 

10.33 
10.60 

~ 

1.08 
0.49 

5.01 
5.05 

— 

100.00 
99.19 

Theory 
XXIX 

55.35 
55.24 

28.23 
29.02 

— 

~ 

10.33 
9.91 

0.19 

1.08 
1.31 

5.01 
5.13 

— 

100.00 
100.80 

Belter 

Theory 
XLI 

55.35 
55.22 

28.23 
28.93 

— 

— 

10.33 
9.95 

~ 

1.08 
0.28 

5.01 
5.01 

— 

100.00 
99.39 

» 

Theory 
XLIII 

55.35 
54.76 

28.23 
29.09 

— 



10.33 
10.10 

— 

1.08 
0.62 

5.01 
5.00 

- 

100.00 
99.57 

» 

Theory 
XLII 

55.35 
55.95 

28.23 
28.41 

— 

___ 

10.33 

9.85 

z 

1.08 
0.43 

5.01 
5.05 

— 

100.00 
99.67 

G.  v.  Rath 

Theory 
CLXXI 

55.35 
55.64 

28.23 
28.89 

— 

__ 

10.33 
10.92 

z 

1.08 
0.71 

5.01 
5.09 

- 

100.00 
101.25 

Delter 

Theory 
XLIV 

55.35 
55.93 

28.23 
28.15 

z 

— 

10.33 

9.84 

z 

1.08 
0.69 

5.01 
5.27 

— 

100.00 
99.88 

Delesse 

Theory 
XLVIII 

55.35 
56.05 

28.23 
28.11 

— 

— 

10.33 
10.10 

— 

1.08 
0.99 

5.01 
4.65 

— 

100.00 
99.90 

G.  v.  Rath 

Theory 
CV 

55.60 
55.86 

28.35 
28.10 

— 

— 

11.03 
10.95 

— 

— 

5.02 
5.09 

— 

100.00 
100.00 

» 

Theory 
XCVII 

55.31 
55.64 

28.21 
28.19 

1.02 

— 

9.68 
9.79 

0.19 

1.08 
2.63 

5.72 

5.48 

— 

100.00 
100.44 

E.  E.  Schmid 

Theory 
XXI 

54.56 
53.41 

24.35 

24.88 

5.46 
4.89 

— 

9.55 
9.42 

0.44 
0.44 

— 

5.64 
5.62 

— 

100.00 
98.66 

S.  v.  Walters- 
hausen 

Theory 
CLI 

53.55 
53.75 

27.31 
27.06 

0.99 

— 

9.37 
9.58 

0.45 
0.47 

7.34 
7.53 

1.38 
1.25 

0.60 
0.62 

100.00 
101.25 

Abich 

Theory 
LXVII 

54.63 
53.48 

26.71 
26.46 

1.82 
1.60 

0.81  MnO 
0.89  MnO 

9.56 
9.47 

1.82 
1.74 

0.22 

4.23 
4.10 

0.42 
0.42 

100.00 
98.40 

Ricciardi 

Theory 
LXXII 

53.51 
53.33 

26.15 
26.13 

1.78 
2.87 

0-79  MnO 
0.59  MnO 

9.99 
10.34 

1.78 
1.64 

1.05 
0.51 

4.15 
3.97 

0.80 
0.84 

100.00 
100.22 

S.  v.  Walters- 
hausen 

Theory 
LXX 

53.19 
53.56 

24.87 
25.82 

3.55 
3.41 

— 

11.79 
11.68 

0.44 
0.52 

1.04 
0.58 

4.12 
4.00 

1.00 
0.95 

100.00 
100.42 

Hunt 

Theory 
CXLV 

53.75 
53.10 

27.42 
26.80 

1.35 

— 

11.92 
11.48 

0.89 
0.72 

1.05 
0.71 

4.16 
4.24 

0.81 
0.60 

100.00 
99.00 

Streng 

Theory 
III 

53.68 
53.11 

27.38 

27.27 

z 

2.42 
2.53 

7.51 

7.47 

0.89 
0.91 

1.05 
1.08 

4.85 
5.09 

2.22 
2.38 

100.00 
99.84 

Jannasch 

Theory 
CLV 

53.76 
54.09 

27.42 
27.82 

- 

1.61 
1.50 

11.29 
11.20 

0.05 

1.06 
0.43 

4.86 
4.76 

0.19 

100.00 
100.04 

Williams 

Theory 
LVIII 

54.38 
55.04 

27.74 
28.09 

— 

~ 

10.79 
10.65 

z 

1.06 
1.26 

5.62 
5.61 

0.41 
0.50 

100.00 
101.15 

Dulk 

Theory 
VII 

54.15 
54.66 

27.62 

27.87 

— 

— 

12.64 
12.01 



— 

5.59 
5.46 

z 

100.00 
100.00 

K.  v.  Hauer 

Theory 
XL 

53.69 
54.53 

27.37 
27.37 





9.39 
9.62 



2.10 
1.81 

6.24 
5.98 

1.21 
1.21 

100.00 
100.52 

Hunt 

Theory 
CXXVI 

54.58 
54.45 

27.84 
28.05 

0.45 

z 

9.55 
9.68 

z 

1.07 
1.06 

6.35 
6.25 

0.61 
0.55 

100.00 
100.49 

Domeyko 

Theory 
XCI 

52.38 
50.50 

25.60 
25.40 

1.75 
2.10 

z 

12.83 
12.25 

0.35 

___ 

7.44 
7.30 

0.04 

100.00 
97.94 

422 


THE   FELSPAR   GROUP 


D.  Felspars  of  the  type 

Si  •  R  •  Si  •  Si  •  R  •  Si  =  6  R203  •  22  Si02 


Source 

123 

4  MO 

•6R203 

22  SiO2 

4  MO  =  2.5  Na2O  •  0.5  CaO  •  0.5  MgO 

Andesine 

Mairus  (Ar- 

•3H20 

•0.5K2O  ;  6R2O3=5.75Al2O3-0.25Fe2O3 

dennes) 

124 

5  MO 

•6A1203 

•  22  SiO2 

5  MO  =  2.  75  Na2O  -2.25  CaO 

Jt 

Tilasinvuori 

•2H20 

125 

6  MO 

•  6  A12O3 

•  22  Si02 

6  MO  =  1.75  Na20  •  3.25  CaO  •  0.75  H2O 
•0.25  MgO 

M 

St.  Raphael 
in  Esterelgeb. 

126 

99 

j? 

99 

6  MO  =  2  Na2O  •  3.25  CaO  •  0.5  H2O 

>f 

Chateau 

•0.25K20 

Richer,  Can. 

127 

99 

» 

99 

6  MO  =  2  Na2O  •  3.25  CaO  •  0.5  H2O 

?J 

Lachute 

•  0.25  K2O 

128 

6  MO 

•6A12O3 

22  SiO2 

6  MO  =  2  Na2O  •  3.5  CaO  •  0.5  K2O 

J? 

St.  Raphael 

•1H20 

in  Esterelgeb. 

129 

6  MO 

•6A12O3 

•  22  SiO2 

6  MO  =  2  Na20  •  3.75  CaO  •  0.25  K2O 

- 

St.  Joachim 

130 

» 

« 

» 

6MO  =  2Na2O-4CaO 

Labradorite 

Ojamo 

131 

M 

79 

»> 

6  MO  =  2.25  Na2O  •  3.5  CaO  •  0.25  K2O 

Andesine 

St.  Raphael 

in  Esterelgeb. 

132 

M 

M 

» 

„ 

Labradorite 

Labrador 

133 

„ 

» 

»» 

„-- 

» 

Krakatan 

134 

6  MO 

•6A1203 

•  22  SiO2 

Andesine 

Chateau 

•1H20 

Richer,  Can. 

135 

6  MO 

•  6  A12O  • 

22  SiO2 

„ 

s> 

Sanford,  Me. 

•2H2O 

136 

6  MO 

•6A1203 

•  22  SiO2 

6  MO  =  2.25  Na2O  •  3.75  CaO 

» 

Tunguragua 

137 

6  MO  =  2.5  Na2O  •  3.25  CaO  •  0.25  MgO 

M 

Nieder- 

mendig 

138 

ft 

M 

tf 

6  MO  =  2.5  Na2O  •  3.5  CaO 

?> 

Guaqua 

Pichincha 

139 

» 

» 

» 

„ 

J> 

Trifail 

140 

M 

»> 

,, 

Labradorite 

Ojamo 

141 

7  MO 

•6A1203 

•  22  SiO2 

7  MO  =  1.75  Na2O  •  4  CaO  •  0.75  H2O 

Andesine 

Gratlue 

•2H20 

•  0.5  K2O 

142 

7  MO 

•6A1203 

•  22  Si02 

7MO  =  1.75  Na2O  •  4.25  CaO  •  0.75  H2O 

Labradorite 

Monte 

•1H20 

•  0.25  K2O 

Amiata 

143 

7  MO 

•6A1203 

•  22  Si02 

7  MO  =  1.75  Na2O  •  5  CaO  •  0.25  MgO 

» 

Verespatek 

144 

7  MO  =  2  Na2O  •  3  CaO-1  FeO-0.75  K2O 

Andesine 

Luccivna, 

•  0.25  MgO 

N.  Tatra 

145 

7  MO 

•6A1203 

•  22  SiO2 

7  MO  =  2  Na2O-3  CaO-1  FeO-0.75  K2O 

}r 

,, 

•5H2O 

•0.25  MgO 

146 

9  MO 

•  6  A1203 

•  22  SiO2 

9  MO  =  2  Na2O  -6.75  CaO  -0.25  MgO 

}> 

St.  Raphael 

•3H2O 

in  Esterelgeb 

THE   FELSPAR   GROUP 


423 


or  the  general  formula 


m  MO  •  6  R203  •  22  Si02  •  n  H20. 

Analyst 

Si02 

A120, 

Fe203 

FeO 

CaO 

MgO 

K20 

Na20 

H20 

Total 

Klement 

Theory 

58.65 

26.06 

1.78 

— 

1.24 

0.89 

2.09 

6.89 

2.40 

100.00 

LXVIII 

59.78 

26.69 

2.05 

— 

1.35 

0.58 

1.69 

7.29 

225 

101.68 

Wilk 

Theory 

58.37 

27.06 

— 

— 

6.16 

— 

— 

6.82 

1.59 

100.00 

LXXVIII 

58.39 

26.68 

— 

— 

5.63 

— 

— 

7.69 

1.61 

10000 

Deville 

Theory 

58.78 

27.25 

— 

— 

8.10 

0.44 

— 

4.83 

0.60 

100.00 

LVI 

59.07 

26.67 

— 

— 

7.96 

0.58 

Trace 

4.95 

0.77 

100.00 

Hunt 

Theory 

58.13 

26.95 





8.02 



1.04 

5.46 

0.40 

100.00 

CXXI 

58.50 

25.80 

1.00 

— 

8.06 

0.20 

1.16 

5.45 

0.40 

100.57 

>? 

Theory 

58.13 

26.95 

— 

— 

8.02 

— 

1.04 

5.46 

0.40 

100.00 

cxxv 

58.15 

26.09 

0.50 

— 

7.78 

0.16 

1.21 

5.55 

0.45 

99.89 

Rammelsberg 

Theory 

56.98 

26.41 



— 

8.46 



2.03 

5.35 

0.77 

100.00 

LV 

58.32 

26.52 

— 

— 

8.18 

0.11 

2.36 

5.27 

0.60 

101.36 

Hunt 

Theory 

57.66 

26.72 



— 

9.17 



1.03 

5.42 

— 

100.00 

CXXIV 

57.55 

27.10 

0.20 

— 

8.73 

— 

0.79 

5.38 

— 

99.75 

Bonsdorff  and 

Theory 

57.90 

26.85 





9.82 



— 

5.43 

— 

100.00 

Laurell 

CXIV 

57.69 

26.00 

0.67 

— 

9.87 

— 

— 

5.50 

— 

99.73 

Rammelsberg 

Theory 

57.62 

26.71 

— 

— 

8.55 

— 

1.03 

6.09 

— 

100.00 

LIX 

58.03 

26.64 

— 

— 

8.07 

— 

0.97 

6.16 

0.30 

99.87 

Lemberg 

Theory 

57.62 

26.71 





8.55 



1.03 

6.09 

— 

100.00 

CLVII 

57.36 

27.01 

— 

— 

8.55 

— 

0.65 

6.03 

— 

100.00 

n 

Theory 

57.62 

26.71 





8.55 



1.03 

6.09 

— 

100.00 

CXXV 

58.29 

27.19 

— 

— 

8.27 

— 

1.22 

5.82 

— 

100.79 

Hunt 

Theory 

57.17 

26.51 





8.49 



1.02 

6.04 

0.77 

100.00 

CXXIII 

57.20 

26.40 

0.40 

— 

8.34 

— 

0.84 

5.83 

0.65 

99.60 

Payne 

Theory 

56.72 

26.30 





8.42 



1.01 

6.00 

1.55 

100.00 

CXVI 

56.65 

25.56 

0.22 

— 

8.25 

— 

1.34 

6.18 

1.58 

99.78 

G.  v.  Rath 

Theory 

57.86 

26.82 





9.20 





6.12 

— 

100.00 

CII 

57.80 

26.75 

— 

— 

9.05 

— 

— 

6.40 

— 

100.00 

Laspeyres 

Theory 

57.92 

26.86 





7.98 

0.44 



6.80 

— 

100.00 

X 

57.29 

26.78 

— 

— 

8.01 

0.28 

— 

6.84 

Trace 

99.20 

G.  v.  Rath 

Theory 

57.82 

26.81 





8.58 

__ 



6.79 

— 

100.00 

C    " 

58.15 

26.10 

— 

— 

9.05 

— 

— 

6.70 

— 

100.00 

Maly 

Theory 

57.82 

26.81 

— 



8.58 



— 

6.79 

— 

100.00 

XLVII 

57.53 

26.62 

— 

— 

8.48 

0.23 

0.39 

6.90 

— 

100.15 

Williams 

Theory 

57.82 

26.82 





8.58 





6.78 

— 

100.00 

cxv 

57.75 

26.15 

0.60 

— 

8.48 

— 

— 

6.25 

— 

99.23 

Heddle 

Theory 

55.91 

25.92 





9.49 



1.99 

4.60 

2.09 

100.00 

LXXII 

56.30 

25.71 

0.97 

— 

9.35 

— 

1.49 

4.72 

1.82 

100.36 

Williams 

Theory 

56.56 

26.23 





10.20 



1.01 

4.65 

1.35 

100.00 

LVI 

55.68 

26.66 

— 

— 

10.30 

— 

1.43 

4.70 

1.23 

100.00 

Sipocz 

Theory 

56.64 

26.26 





12.02 

0.42 

— 

4.66 

— 

100.00 

XXXVII 

55.21 

25.56 

1.00 

— 

11.76 

0.53 

— 

4.37 

— 

101.43 

Hofer 

Theory 

55.54 

25.75 



3.03 

7.07 

0.42 

2.97 

5.22 

— 

100.00 

XXIX 

56.04 

25.55 

— 

3.12 

7.19 

0.59 

2.59 

4.92 

— 

100.00 

j> 

Theory 

53.51 

24.81 



2.92 

6.81 

0.41 

2.86 

5.03 

3.65 

100.00 

XXVIII 

53.26 

24.28 

— 

2.96 

6.83 

0.56 

2.47 

4.68 

3.98 

99.02 

Deville 

Theory 

52.84 

24.51 





15.13 

0.40 

— 

4.96 

2.16 

100.00 

LVIII 

52.42 

24.78 

— 

— 

15.02 

0.51 

0.14 

5.10 

2.03 

100.00 

424 


THE   FELSPAR   GROUP 


Si  •  R  •  Si  •  Si 


E.  Felspars  of  the  type 
R  •  SAi  =  6  R2O3  •  24  Si02 


Source 

147 

4  MO  •  6  R2O3 

•  24  Si02 

4  MO  =  2  Na2O  •  0.  75  CaO    0.  75  K2O 

Oligoclase 

Helsingfors 

•6H2O 

•0.5  MgO  ;  6  R2O3=5.5  A12O3-0.5  Fe2O3 

148 

4  MO  •  6  A12O9 

•  24  SiO2 

4  MO  =  2  Na2O  •  1.75  CaO  •  0.25  K2O 

if 

Tokowaja 

149 

4  MO  =  2.25  Na2O  •  1.5  CaO  •  0.25  K2O 

M 

Bakersville,  N.C. 

150 

5  MO  •  6  A1203 

•24Si02 

5  MO  =  2  Na2O  •  2  CaO  •  1  K2O 

Andeaine 

Horberig 

151 

5  MO  •  6  R2O3 

•24SiO2 

5MO  =  5Na20  •  2.25  CaO  -  0.75K2O 

Milltown 

•5H20 

6  R2O3  =  5.5  A12O3  •  0.5  Fe2O3 

152 

5  MO    6  A12O3 

•  24  Si02 

5  M0  =  2.25  Na2O  •  2  CaO  •  0.75  K2O 

Oligoclase 

Durrmorsbach 

•2H2O 

153 

5  MO  •  6  R2O3 

•  24  SiO2 

5  MO  =  2.5  Na2O  •  2  CaO  •  0.5  K2O 

?» 

Ardara 

6  R2O3=5.75  A12O3  •  0.25  Fe2O3 

154 

5  MO  •  6  A1,O3 

•  24  SiO2 

5  MO  =  2.5  Na2O  •  2.5  CaO 

Andesine 

Milltown 

•  1  H2O 

Csicso-Berg 

155 

5  MO  •  6  A12O« 

•  24  SiO2 

5  MO  =  2.75  Na2O  •  1.5  CaO  •  0.75  K2O 

Oligoclase 

Allemont 

•  2  H2O  ' 

156 

5  MO  •  6  A12O3 

•24SiO2 

5  MO  =  2.75  Na2O  •  1.5  CaO  •  0.5  MgO 

>» 

Bourg  d'Ofsans 

•  2  H2O 

•0.25K2O 

157 

5  MO  •  6  A1203 

•  24  Si02 

5MO  =  3Na2O-2CaO 

>» 

Carter-MineN.C. 

158 

6  MO  •  6  A1203 

•  24  SiO2 

6  MO  =  1.5  Na20  •  4  CaO  •  0.25  K2O 

Andesine 

Kyffhauser 

•1H20 

•  0.25  FeO 

159 

6  MO  •  6  A1203 

•  24  SiO2 

6  MO  =  2  Na2O  •  3.25  CaO  -  0.5  H2O 

M 

Chateau  Richer, 

•  0.25  K20 

Canada 

160 

»           » 

» 

6  MO  =  2.25  Na2O  •  3.25  CaO-0.25  MgO 

>» 

Frauenberg  bei 

•0.25K20 

Schluchtern 

161 

6  MO  •  6  A12O3 

•  24  SiO2 

6  MO  =  2.  5  NanO  •  2.25  CaO  •  0.75  MgO 

n 

La  Bresse 

•1H20 

•0.5K20 

162 

6MO-6A1203 

•  24  SiO2 

6  MO  =  2.5  Na2O  •  2.5  CaO  •  0.5  K2O 

19 

Cullakenee, 

•1H20 

•  0.5  H2O 

Clay  Co.,  N.C. 

163 

6  MO  •  6  A12O3 

•24SiO2 

6  MO  =  2.5  Na2O  •  2.5  CaO  •  0.75  H0O 

n 

Faymont 

•1H20 

•  0.25  K20 

164 

6  MO  •  6  A12O3 

•  24  Si02 

6  MO  =  2.5  Na2O  •  2.5  CaO  •  0.75  H2O 

Sebesvar 

•lHaO 

•0.25K2O 

165 

6  MO  •  6  R2O3 

24SiO2 

6  MO  =  2.5  Na2O  •  2.5  CaO  •  0.75  MgO 

Marmato 

0.25K20;6R203=5.75Al203-0.25Fe203 

bei  Popayan 

166 

6  MO  •  6  A12O3 

•  24  Si02 

6  MO  =  2.5  Na2O  •  2.75  CaO  •  0.5  H2O 

s> 

Coromandel 

•  0.25  K2O 

167 

»           >j 

,, 

6  MO  =  2.5  Na2O  •  3  CaO  •  0.25  MgO 

t_ 

Budenmais 

•  0.25  H2O 

168 

»>           » 

» 

6  MO  =  2.5  Na2O  •  3.5  CaO 

>» 

Pululagua 

169 

6  MO  •  6  A12O3 

•24Si02 

6  MO  =  2.  75  Na2O  •  1.5  CaO  •  1  K.O 

Oligoclase 

Unionville,  Pa. 

•  2  H2O  ' 

•  0.5  H20-  0.25  MgO 

170 

6  MO  •  6  A12O3 

•  24  Si02 

6  MO  =  2.  75  Na2O  •  2  CaO  •  0.5  K2O 

Andesine 

Servance 

•1H2O 

•  0.5  H20-  0.25  MgO 

THE   FELSPAR  GROUP 


425 


or  the  general  formula 

m  MO  •  6  R2O3  •  24  Si02  •  n  H20. 


Analyst 

SiOa 

AIsO, 

Fe203 

FeO 

CaO 

MgO 

KaO 

Na,0 

Hao 

Total 

Lemberg 

Theory 

58.88 

22.94 

3.27 

— 

1.72 

0.82 

2.88 

5.07 

4.42 

100.00 

CVI 

58.30 

23.15 

4.09 

— 

1.65 

0.59 

2.52 

5.26 

4.44 

100.00 

Jewreinow 

Theory 

62.68 

26.64 

— 

— 

4.26 

— 

1.02 

5.40 



100.00 

cxv 

60.63 

26.35 

0.40 

— 

4.15 

0.25 

1.17 

5.60 

— 

98.55 

Clarke 

Theory 

62.64 

26.61 

— 

— 

3.65 

— 

1.02 

6.07 

— 

100.00 

CXXIX 

62.92 

25.32 

— 

— 

4.03 

— 

0.96 

6.18 

0.25 

99.66 

Knop 

Theory 

60.45 

25.69 

— 

— 

4.71 

— 

3.94 

5.21 

— 

100.00 

XVII 

60.01 

25.49 

— 

— 

4.71 

— 

4.06 

5.77 

— 

100.04 

Heddle 

Theory 

57.81 

22.51 

3.21 

— 

5.06 

— 

2.83 

4.97 

3.61 

100.00 

LXIX 

58.38 

22.50 

2.12 

O.lSMnO 

5.34 

— 

3.20 

5.21 

3.41 

100.31 

Haushofer 

Theory 

59.75 

25.40 

— 

— 

4.65 

— 

2.92 

5.79 

1.49 

100.00 

XXIX 

59.30 

25.75 

— 

— 

4.79 

— 

2.78 

5.63 

1.29 

99.54 

Haughton 

Theory 

60.49 

24.64 

1.68 

— 

4.71 

— 

1.97 

6.51 

— 

100.00 

LXIII 

59.28 

22.96 

1.94 

0.32  MnO 

4.65 

0.21 

2.38 

6.48 

— 

98.22 

Koch 

Theorv 

60.89 

25.88 

— 

— 

5.92 



— 

6.55 

0.76 

100.00 

XL  VI 

61.62 

25.47 

— 

— 

5.72 

— 

— 

6.31 

0.88 

100.00 

Lory 

Theory 

59.68 

25.36 

— 

— 

3.48 



2.92 

7.07 

1.49 

100.00 

LIV 

59.40 

24.20 

0.60 

— 

3.70 

— 

3.80 

7.00 

1.50 

99.80 

5> 

Theory 

60.35 

25.65 

— 

— 

3.52 

0.84 

0.98 

7.15 

1.51 

100.00 

LV 

59.90 

25.10 

— 

— 

3.70 

0.70 

1.20 

7.40 

1.70 

99.70 

Keller 

Theory 

61.29 

26.04 

— 

— 

4.76 



— 

7.91 

— 

100.00 

CXXXI 

62.32 

25.19 

— 

— 

5.01 

— 

0.25 

8.02 

— 

10079 

Streng 

Theory 

59.30 

25.20 

— 

0.74 

9.23 



0.96 

3.83 

0.74 

100.00 

V    * 

59.16 

25.97 

— 

1.04 

9.23 

0.03 

0.47 

3.91 

0.68 

100.49 

Hunt 

Theory 

60.24 

25.60 

— 

— 

7.61 



0.98 

5.19 

0.38 

100.00 

CXVII 

59.55 

25.62 

0.75 

— 

7.73 

Trace 

0.96 

5.09 

0.45 

100.15 

Wedel 

Theory 

59.82 

25.42 

— 

— 

7.65 

0.43 

0.98 

5.79 

— 

100.00 

VII 

59.19 

25.77 

0.34  (Fe2Oa+FeO) 

7.27 

0.27 

0.80 

5.88 

0.37  Ti02 

99.89 

Delesse 

Theory 

59.31 

25.21 

— 

— 

5.19 

1.24 

1.93 

6.38 

0.74 

100.00 

XVI 

58.55 

25.26 

0.30 

— 

5.03 

1.30 

1.50 

6.44 

0.91 

99.29 

Chatard 

Theory 

59.48 

25.28 

— 

— 

5.78 



1.94 

6.40 

1.12 

100.00 

CXV 

58.41 

25.93 

0.38 

— 

5.82 

0.18 

2.10 

6.42 

0.93 

100.20 

Delesse 

Theory 

59.96 

25.48 

— 

— 

5.83 



0.97 

6.45 

1.31 

100.00 

XV 

59.38 

25.57 

— 

— 

6.50 

— 

7.03 

1.25 

100.00 

K.  v.  Haue 

Theory 

59.96 

25.48 





5.83 



0.97 

6.45 

1.31 

100.00 

XLII 

59.50 

25.48 

— 

— 

5.82 

— 

1.43 

6.43 

1.35 

100.07 

Abich 

Theory 

59.63 

24.28 

1.66 



5.80 

1.24 

0.97 

6.42 



100.00 

CVI 

59.60 

24.28 

1.58 

— 

5.77 

1.08 

1.08 

6.53 

— 

99.92 

Dirvell 

Theory 

60.16 

25.57 

— 



6.43 



0.98 

6.48 

0.38 

100.00 

LXXXIV 

61.32 

25.30 

— 

— 

6.50 

— 

1.19 

6.30 

0.50 

101.11 

Foullon 

Theorv 

59.79 

25.41 

— 

— 

6.99 

0.41 

0.97 

6.43 

— 

100.00 

XXVI 

59.22 

25.08 

0.96 

— 

7.08 

0.28 

0.54 

6.79 

— 

100.78 

G.  v.  Rath 

Theory 

59.93 

25.47 





8.15 





6.45 



100.00 

XCIX 

59.39 

26.08 

— 

— 

820 

— 

0.22 

6.74 

— 

100.63 

Chatard 

Theorv 

58.65 

24.92 





3.42 

0.41 

3.83 

6.94 

1.83 

100.00 

CXXXVII 

59.35 

24.16 

0.61 

— 

3.08 

0.34 

3.78 

7.22 

1.96 

100.50 

Delesse 

Theory 

59.54 

25.31 

— 

— 

4.63 

0.41 

1.94 

7.05 

1.12 

100.00 

XIII 

58.92 

25.05 

— 

— 

4.64 

0.41 

2.06 

7.20 

1.27 

99.50 

THE   FELSPAR   GROUP 


Source 

171 

6  MO    6A1203 

•  24  Si02 

6MO  =  2.75Na,0-2.25CaO-0.75K2O 
•0.25MgO 

Oligoclase 

Beloceil 

172 

„ 

n 

6  MO  =  2.75  Na20  •  3  CaO  •  0.25  K2O 

Andesine 

Heubach 

173 

»            > 

H 

J5                             »«                             >J                             » 

» 

(Chateau  Richer, 
Canada)  Toluca 

174 

»           >» 

»> 

6MO  =  3Na20  •  1.75  CaO  •  0.75  H2O 
•0.25MgO-0.25K2O 

Oligoclase 

Norway 

175 

6MO-6A1203 
•1H20 

24  SiO2 

6  MO  =  3  Na2O  •  1.75  CaO  •  0.75  K2O 
•0.25MgO-0.25H2O 

Andesine 

Coravillers 

176 

6  MO  •  6  A12O3 
•1H20 

•  24  SiO2 

6  MO  =  3  Na2O-2  CaO-0.5  K2O-0.5H2O 

Oligoclase 

Altai 

177 

6  MO    6R2O, 
-3H20* 

24  SiO2 

6  MO  =  3  Na2O  •  2.5  CaO  •  0.25  MgO 
•0.25Na20;6R203=5.75Al203-0.25Fe203 

Andesine 

Frankenstein 

178 

6  MO  •  6  A12O3 

•  24  SiO2 

6  MO  =  3  Na2O  •  2.75  CaO  -  0.25  K2O 

" 

Marmato 
bei  Popayan 

179 

»>           » 

j> 

6MO  =  3Na2O-3CaO 

» 

Mojanda 

180 

»           »> 

H 

6MO  =  3.75Na2O-  2.25  CaO 

H 

Bodenmais 

181 

6  MO  •  6  A12O3 
•3H20 

•24Si02 

6MO  =  4Na2O-2CaO 

J> 

» 

182 

7  MO  •  6  A12O8 
•3H20 

•  24  SiO2 

7  MO  =  2.5  Na,O  •  3.25  CaO  •  0.75  H2O 
•"0.5K2O 

J> 

Szaszka 

183 

7MO-6R203 
•1H20 

•  24  SiOa 

7  MO  =  2.5  Na2O  •  3.5  CaO  •  0.5  K2O 
•0.5H2O;6R2O3=5.75Al2O3-0.25Fe2O3 

» 

Chateau  Richer, 
Canada 

184 

7MO-6A1203 
-2H20 

•  24  SiO2 

7  MO  =  2.75  Na2O  •  3.5  CaO  •  0.75  K2O 

" 

Delnabo 
Glen  Gairu 

185 

7  MO  •  6  A12O, 
•2H20 

•  24  SiO2 

7  MO  =  3  Na2O  •  3.25  CaO  •  0.5  K2O 
•0.25H20 

H 

Nagy  Sebes 

186 

7  MO  •  6  A12O3 

•  24  SiO2 

7  MO  =  3  Na2O  •  3.25  CaO  •  0.5  K2O 
•0.25MgO 

* 

Marmato 
bei  Popayan 

187 

„ 

» 

7  MO  =  3.5  Na2O  •  3  CaO  •  0.5  MgO 

Oligoclase 

Baumgarten 

THE   FELSPAR   GROUP 


427 


Analyst 

Si02 

A1203 

Fe203 

FeO      |   CaO 

MgO 

K20 

NatO 

HtO 

Total 

Hoffmann 

Theory 
CXLV 

59.28 
58.30 

25.19 
24.72 

Z 

— 

5.19 
5.42 

0.42 
0.91 

7.02 
2.74 

7.02 
6.72 

0.50 

100.00 
99.32 

Petersen 

Theory 
XX 

59.66 

58.77 

25.36 
25.30 

0.31  (1 

^e2Os+FeO) 

6.95 
6.90 

0.18 

0.97 
0.60 

7.06 
6.67 

0.28  TiO2 

100.00 
99.01 

G.  v.  Rath 

Theory 
CXIII 

59.66 
59.79 

25.36 
25.43 

— 

— 

6.95 
7.41 



0.97 
0.64 

7.06 
7.24 



100.00 
100.51 

Dirvell 

Theory 
LXXV 

60.42 
61.14 

25.68 
25.10 

— 

— 

4.11 

4.39 

0.42 
0.50 

0.99 
1.17 

7.81 
7.66 

0.57 
0.80 

100.00 
100.76 

Delesse 

Theory 
XIV 

59.04 
58.91 

25.09 
24.59 

0.99 

— 

4.02 
4.01 

0.41 
0.39 

2.89 
2.54 

7.63 
7.59 

0.92 
0.98 

100.00 
100.00 

Christschoff 

Theory 
CXVIII 

59.16 

58.89 

25.15 
25.38 

z 

— 

4.60 
4.69 

— 

1.93 
1.35 

8.05 
7.65 

1.11 
1.17 

100.00 
99.25 

Schmidt 

Theory 
I 

58.10 
58.93 

23.70 
23.50 

1.61 
1.27 

0.75NiO 
0.39  NiO 

5.66 
5.67 

0.40 
0.56 

0.50 

7.52 
7.42 

2.18 
2.21 

100.00 
100.00 

Rammels- 
berg 

Theory 
CVII 

59.62 
60.26 

25.23      — 
25.01      — 

— 

6.38 
6.87 

0.14 

0.97 
0.84 

7.70 

7.74 



100.00 
100.86 

G.  v.  Rath 

Theory 
XCVIII 

59.85 
60.48 

25.44 
25.35 

— 



6.98 
7.25 

— 

0.08 

7.73 

7.28 

— 

100.00 
100.44 

A.  Ohl 

Theory 
XXIV 

59.74 
60.35 

25.39 
26.13 

— 



5.23 
5.14 

— 



9.64 
9.32 

— 

100.00 
100.94 

H.  Schulze 

Theory 
XXIII 

5926 
58.36 

25.17 
25.72 

— 

4.62 
4.76 

z 

— 

10.21 

10.18 

0.74 
0.51 

100.00 
99.63 

Sommaruga 

Theory 
XXXIX 

57.52 
56.51 

24.46 
24.94 

— 

— 

7.26 
7.08 

z 

1.88 
1.28 

6.19 
6.37 

2.69 
2.55 

100.00 
98.73 

Franke 

Theory 

cxx 

57.80 
58.38 

23.53 
23.86 

1.61 
1.18 

— 

7.87 
7.83 

— 

1.89 
1.68 

6.22 
6.05 

1.08 
1.03 

100.00 
100.11 

Heddle 

Theorv 
LXXI 

57.03 
56.96 

24.23 
23.81 

0.94 

— 

7.77 
7.98 

0.09 

2.79 
2.56 

6.75 
6.85 

1.43 
1.62 

100.00 
100.81 

K.  v.  Hauer 

Theory 
XLI 

57.42 
57.20 

24.41 
25.12 

~ 

z 

7.26 
6.96 

__ 

1.87 
1.87 

7.42 

7.28 

1.62 
1.68 

100.00 
100.11 

Jacobson 

Theory 
CVIII 

58.13 
60.14 

24.71 
25.39 

0.87 

z 

7.35 
7.93 

0.40 
0.53 

1.90 
1.66 

7.51 

7.99 



100.00 
104.51 

Varrentrapp 

Theory 
III 

58.61 
58.41 

24.92 
25.23 

— 

— 

6.83 
6.54 

0.81 
0.41 

— 

8.83 
9.39 

— 

100.00 
99.98 

428 


ALLOPHANES  AND  CLAYS 


A.  Formulae  from  a  Series  of  Analyses  of  Allophanes. 


I 

0.5  CaO 

6  A1203 

6  Si02     32  H20 

II. 

0.5  CaO 

6  A12O3 

6  Si02 

38  H2O 

Calcd. 
Found 

1.77 

1.92 

38.77 
37.73 

22.96 
23.53 

36.50 

36.86 

Calcd. 
Found 

1.66 
1.96 

36.29 
35.20 

21.48 
21.39 

40.57 
40.86 

III. 

0.75  CaO 

6  A1203 

6  SiO2     32  H2O 

IV.    0 

.25  CaO 

6  A1203 

5  Si02 

32H,0 

Calcd. 
Found 

2.63 
2.83 

38.44 
38.76 

22.75 
22.65 

36.17 
35.14 

Calcd. 
Found 

0.93 
0.70 

40.69 
41.00 

20.07 
19.80 

-^^-2  ^ 

38.30 
37.70 

V.  0.75  CaO     6  Al 

203 

6Si02 

42H20 

Calcd. 

2.37          34. 

53 

20.45 

42.65 

Found 

2.23          31 

.34 

20.50 

42.91 

B.  Formulae  from  Clay  Analyses  in  C.  Bischof  s  Book. 

(a)  Si  •  E  •  Si. 


K,0 

MgO 

CaO  |  Fe203 

Al,o, 

Si02 

H2o 

Na2o|   Total 

K2o 

Ka03 

SiOj 

H2o 

5.37 
5.65 
4.90 
4.69 

Page  |                             source 

2.87 
0.27 
3.15 
1.45 

0.28 
0.54 
0.52 
0.54 

0.23 
0.13 
0.10 
0.51 

0.44 
3.06 
1.12 

0.83 

26.73 
24.52 
26.27 
26.93 

61.46 
62.73 
61.35 
62.66 

8.26 

8.88 
7.53 

7.38 

— 

100.27 
100.13 
100.04 
100.30 

0.48 
0.21 
0.56 
0.43 

3.10 
2.98 
3.10 
3.09 

12.00 
12.00 
12.00 
12.00 

78 
66 
68 
68 

Mahren,  Briesen 
Goppersdorf,  Silesian  Prussia 
Tschirne,  Silesian  Prussia 
»»               »             » 

(b)  Si  -  R  -  Si. 


K,o|MgO 

CaO 

Fe20a 

A1203|  Si02 

H20 

Na8O 

Total 

E2o 

E203 

Si02 

H20 

Page 

Source 

2.11 
2.11 
1.24 
2.99 
1.26 
0.88 
1.26 
0.75 
0.73 
0.54 
0.60 

Trace 
0.47 
0.55 
0.37 
0.28 
0.33 
0.24 
0.34 
0.15 
Trace 
0.13 

0.15 
0.40 
0.61 
0.26 
0.34 
0.36 
0.13 
0.28 
0.46 
0.07 
0.12 

3.42 
1.86 
2.03 
1.35 
1.71 
1.04 
0.97 
1.17 
0.89 
1.16 
0.76 

26.94 
28.55 
27.98 
28.31 
28.31 
29.26 
28.88 
29.15 
29.57 
28.68 
29.99 

58.02 
58.35 
56.59 
59.01 
59.78 
57.97 
58.63 
58.26 
57.71 
59.58 
58.04 

9.39 
8.59 
9.92 
7.93 
8.27 
9.98 
10.50 
10.00 
10.68 
9.87 
10.59 

1.08  C. 

0.052 
0.09  S. 

0.08  S. 

100.03 
100.33 
100.15 
100.22 
100.02 
99.91 
100.01 
100.05 
100.19 
99.90 
100.31 

0.26 
0.42 
0.39 
0.46 
0.26 
0.25 
0.22 
0.22 
0.21 
0.07 
0.12 

2.95 
2.99 
3.03 
2.91 
2.89 
3.03 
2.90 
3.02 
3.06 
2.91 
3.08 

10.00 
10.00 
10.00 
10.00 
10.00 
10.00 
10.00 
10.00 
10.00 
10.00 
10.00 

5.39 
4.91 
5.83 
4.48 
4.61 
5.74 
5.97 
5.77 
6.17 
5.52 
6.08 

71 
87 
86 
53 
83 
86 
71 
71 
75 
71 
71 

Lothain  b.  MeiCen,  Saxony. 
Serge  jewka,  Russia. 
Borowitschi,  Russia. 
Neitzert  i.  Bendorf,  Prussia. 
Sonkolyo,  Hungary. 
Borowitschi,  Russia. 
L6thain  b.  MeiBen,  Saxony. 

Michelob,  Bohemia. 
LOthain  b.  Meifien,  Saxony. 

(c)  R 


Si 


K.O 

MgO 

CaO 

Fe203 

A1203 

Si02 

H20 

Na2O 

Total 

E20 

R203|  SiOz 

H20 

Page  1                        Source 

1.02)  — 

— 

1.77|18.93)72.05)6.13J  0.10  S.|lOO.OO|o.l4|2.98|l8.00J5.12|  59  1  GroBalmerode,  Prussia. 

(d) 


M 


K,O 

Mgo|cao|Fe2Oa 

A1203|  Si08 

H2o 

Na20    |   Total 

R20 

K208 

SiO2 

Hao 

Page 

Source 

0.55 
2.19 

0.33 
0.16 

0.18 
0.24 

0.63 
1.67 

23.65 

23.08 

65.69 
65.35 

9.11 
7.46 

0.09  S. 

100.23 
100.15 

0.23 
0.43 

3.22 
3.25 

15.00 
15.00 

6.93 
5.70 

71 
67 

LSthain  b.  MeiSen,  Saxony. 
Ober-Horka,  Prussia. 

0.85 
0.80 

0.08 
0.09 

0.0V 
0.43 

1.40 
0.71 

23.02 
23.61 

67.48 
66.58 

7.34 
7.90 

~*~' 

100.24 
100.12 

0.16 
0.25 

3.12 
3.18 

15.00 
15.00 

5.44 
5.93J 

50 

77 

Dillenburg,  Prussia. 
Blansko,  Mahren. 

CLAYS 

(e)  Si  •  R  -  R  •  Si. 


429 


K20 

MgO 

CaO  |Fe20« 

A120,  |  SiO, 

H,0  |Na20 

Total 

RaO   |R2O8 

Si02 

H2O 

Page 

Source 

0.57 
1.32 
3.00 
2.00 
0.51 

38.46 
0.07 
0.11 
0.18 
0.21 

0.02 
0.06 
0.04 
0.12 
0.32 

0.29 
2.74 
0.95 
1.65 
0.41 

24.51 
37.09 
37.95 
38.17 
37.73 

28.12 
47.22 
46.97 
44.90 
46.21 

6.38 
10.79 
10.02 
12.85 
14.22 

1.87 
0.39 

100.22 
100.19 
99.04 
99.93 
100.02 

24.62 
0.26 
0.54 
0.63 
0.35 

6.19 
5.81 
5.79 
6.16 
5.81 

12.00 
12.00 
12.00 
12.00 
12.00 

9.08 
6.09 
8.53 
11.45 
12.31 

57 
74 
52 
74 
57 

Westerland,  Prussia. 
Eger,  Austria. 
Ebernhalm,  Prussia. 
Eger,  Austria. 
Westerland,  Prussia. 

(f)  Si  •  R  •  R  •  Si. 


K20 

MgO 

CaO 

Fe20, 

A120, 

SiO, 

H2o 

Na,0 

Total 

Eao  |R,O,|  sio, 

H20 

Page 

Source 

4.28    0.950.62 

1.2432.72 

48.92 

11.49 

100.23 

1.18 

4.83 

12.00 

9.39 

78 

Briesen,  Mahren. 

1.64 

15.790.13 

0.33  29.64 

42.53 

7.52 

2.61 

100.91 

7.72 

4.92 

12.00 

7.07 

57 

Westerland,  Prussia. 

2.73 

0.490.32 

2.9433.63 

49.43 

10.59 

— 

100.13 

0.83 

5.09 

12.00 

8.54 

44 

G  runstadt,  Bavaria  . 

3.211  0.410.48 

1.79!33.09 

50.72 

10.49 

— 

100.19 

0.75 

4.77 

12.00 

8.27 

44 

2.30 

0.790.56 

2.2224.76 

49.60 

9.96 

— 

100.19 

0.78 

4.91 

12.00 

8.03 

44 

99                              99 

2.65 

0.690.34 

1.7333.57 

50.39 

10.85 



100.22 

0.73 

4.86 

12.00 

8.61 

44 

3.86 
3.14 

0.630.43  1.27 
0.67  0.40!  2.24 

35.39 
33.91 

49.76 
48.92 

8.83 
10.92 

— 

100.17 
100.10 

0.93 
0.84 

5.12 
5.09 

12.00 
12.00 

7.09 
8.84 

54 

44 

H6hr  b.Grenzhausen.Prus. 
Grunstadt,  Bavaria. 

3.38 

0.550.331  2.07 

34.61 

48.85 

10.18 

— 

99.97 

0.82 

5.19 

12.00 

8.33 

44 

99                                     99 

2.73 

0.450.34 

2.00 

33.76 

50.12 

10.63 

— 

100.03 

0.67 

4.94 

12.00 

8.48 

44 

99                                     99 

1.51 

0.730.76 

1.66 

34.95 

49.48 

11.04 

0.26  S. 

100.39 

0.69 

5.13 

12.00 

8.92 

58 

Grofialmerode,  Prussia. 

1.81 

0.440.48 

1.90 

34.09 

49.49 

11.63 

0.036S. 

99.87 

0.56 

5.03 

12.00 

9.40 

46 

Gem.Mechenhart,Bavaria. 

1.5914.560.02 

0.08 

30.33 

41.14 

10.02 

2.10 

99.84 

7.20 

5.17 

12.00 

9.63 

57 

Westerland,Prussia. 

2.66 

0.21  0.40 

2.00 

33.71 

49.86 

11.13 

— 

99.97 

0.58 

4.95 

12.00 

8.92 

44 

GrunstadtjBavaria. 

3.79 

0.15:0.23 

1.1633.71 

47.76 

13.26 

— 

100.06 

0.72 

5.09 

12.00 

11.10 

80 

Briesen,  Mahren  . 

1.33 

0.76  0.51!  1.84  35.60 

49.66 

10.04 

— 

99.74 

0.67 

5.23 

12.00 

8.09 

44 

Grunstadt,  Bavaria, 

2.78   0.180.33 

1.06 

34.41 

50.03 

11.46 

— 

100.25 

0.57 

4.95 

12.00 

9.16 

76 

Wildstein,  Bohemia. 

1.30    0.280.05 

1.8933.64 

48.23 

14.63 

0.15  S. 

100.78 

0.32 

5.10 

12.00 

12.13 

83 

Gflttweig,  South  Austria. 

1.41    0.230.34 

1.0034.89 

51.17 

10.85 

— 

99.89 

0.38 

5.02 

12.00 

8.48 

77 

Blansko,  Mahren. 

1.04   0.290.21 

0.60,35.71 

50.00 

11.98 

99.94 

0.31 

5.08 

12.00 

9.56 

77 

>»              >» 

(g)  Si  •  R  •  Si  •  R  •  Si. 


K20 

MgO 

CaO  |Fe20, 

A120S 

SiO, 

H,0 

Na,0 

Total 

B,o 

R,0» 

SiO, 

H,0 

Page 

Source 

2.41 
0.38 

0.68'0.42|  1.00J30.11 
0.250.15|0.70|31.71 

56.04 
55.47 

9.441     — 
11.40|     — 

100.10 
100.06 

0.96 
0.25 

5.81 
6.13 

18.00 
18.00 

10.10 
12.33 

68 

72 

Tschirne,  Prussia. 
LOthain  b.  MeiBen,  Saxony. 

(h)  Si  •  R  •  Si  •  R  •  Si. 

K,O  |  MgOJ  CaO  Fe,0,|  A1,OS 

SiO,  |  H2O 

Na,o 

Total  |R,O|R,O, 

SiO, 

H,O 

Page 

Source 

1.67:0.57,0.43 
3.01  0.39  0.42 
&600.311.31 
2.920.28i0.31 
1.370.450.49 
1.37'0.450.49 
0.6l|0.230.13 

1.78 
2.00 
1.20 
1.23 
1.50 
1.50 
0.65 

31.58 
32.54 
30.65 
33.56 
33.11 
34.08 
33.61 

53.1410.69 
50.9110.42 
50.4015.65 
51.961  9.62 
54.66;  8.73 
53.09    8.71 
52.11112.80 

0.04 
0.10 

0.11  S 

99.98J0.71 
99.790.87 
100.120.71 
99.84|1.41 
99.69,0.61 
100.00!0.62 
100.14J0.24 

5.79 
6.25 
5.87 
6.22 
5.93 
6.20 
6.14 

16.00 
16.00 
16.00 
16.00 
16.00 
16.00 
16.00 

10.73 
10.94 
16.56 
9.87 
8.61 
8.75 
13.10 

46 
54 
87 
76 
46 
61 
71 

Gem.Mechenhart,Bavaria. 
H6hr  b.Grenzhausen,Prus. 
Novgorod,  Russia. 
Wildstein,  Bohemia. 
Klingenberg  a.M.  Bavaria. 
Ahrtal,  Prussia. 
Lothain  b.MeiBen,Saxony. 

(i)  Si  •  R  -  Si  •  R  •  Si. 


!K20 

MgO  CaO  |Fe,0,|  A120, 

SiO, 

H,o|    Na,0 

Total  |R,O, 

B,0, 

SiO, 

H20 

Page 

Source 

1.40 

1.99 

0.34J0.10|  0.72|27.40|60.158.00 
030i0.2l|  0.79128.30  60.2118.59 

0.21  FeO 

98.320.45 
100.39|0.57 

4.9lH8.00|7.97  84 
5.06|l8.00|8.59|  49 

Namur,  Belgium. 
Odenwald,Hessen-Dannstadt. 

430 


CLAYS 


C.  Formulae  from  Clay  Analyses  in  C.  Bischofs  Book. 

I          0.5  CaO     2.75A12O3     0.25Fe2O3       15SiO2     5.5  H2O 

Calcd.          2.06  20.72  2.95  66.95          7.32    /Source :  Tiegelerdberg  (Bavaria). 

Found.         2.25  20.97  2.25  66.70          7.53    \Analyst :  H.  Kaul,  1.  c.  p.  47. 

II.      0.25  K2O    19.75  H2O    0.25Fe2O3    9.75A12O3    24  SiO2  (  Source  :  Winkelhaid  (Bavaria). 
Calcd.          0.82  12.42  1.40  34.73         50.62    \  Analyst :  H.  Kaul,  1.  c.  p.  47. 

Found.         0.95  12.11  1.38  35.72         49.80        0.15  CaO    0.18  Na2O    0.09  S 

III.  0.25 MgO  0.25 K20  0.25Fe2O3  5.75  A12O3  16SiO2  1 5. 5  H2O/ Source:  Wolf shohe (Bavaria) 
Calcd.          0.52  1.23  2.09    '      30.77        50.73       14.64    \Analyst :  H.  Kaul,  1.  c.  p.  47. 

Found.         0.59  1.09  1.56  31.26        49.61       14.43        0.26  CaO     0.29  Na2O 

IV.  O.SCaO  15.5H2O  0.25Fe2O3  5.75A12O3  16SiO2/Source  :  Passau  (South  Bavaria). 

Calcd.       1.47        14.68  2.10    '      30.86        50.88  \Kerl, Handb. d. ges. Tonw.  1879, 505, I.e. 48. 

Found.     1.63        14.23  1.05  31.11        51.02       0.80  H2O 


VI. 

Calcd. 
Found. 

0.25  Fe2O3     5.75  A12O3     16  SiO2  /Source  :  Stabbarp  (Sweden). 
2.51     '          36.81    *       60.68    \Analyst  :  Cronquist,  Stockholm  (I.  c.  p.  41). 
1.70              36.10           60.80       0-5  CaO     0.5  K2O     0.2  MgO 

VIII. 
Calcd. 
Found. 

0.5  K20 

2.80 
3.17 

8.5  H2O     5  A12O3     16  SiO2  /Source  :  Finsing  b.  Deggendorf. 
9.12         30.41         57.66  \Analyst  :  C.  Bischof,  1.  c.  p.  43. 
8.67         29.47          57.45       0.75Fe2O3     0.76  (MgO  +  CaO) 

IX. 

Calcd. 
Found. 

0.25  Fe2O 
2.28 
1.79 

3     5.75  A12O3     15  SiO2     0.5  K2O     9.5  H2O  /Source  :  Grunstadt  (Rheinpfalz). 
33.50           51.77          2.68           9.77      \  Analyst  :  C.  Bischof  . 
33.09           50.70          3.21         10.49          0.41  MgO     0.18  CaO 

X. 

Calcd. 
Found. 

6A1203 
45.78 
45.07 

12  SiO2  /Source  :  Altwasser,  Grube  Morgen-  und  Abendstern. 
54.22    \Analyst  :  C.  Bischof  (L  c.  p.  36). 
54.03         0.15  MgO       0.25Fe2O3       0.54  K2O 

XI.      0.25K2O  0.25CaO  0.25Fe2O3  5.75A12O3  16  SiO2 

Calcd.         1.44          0.86  2.45  35.96       59.29/Source :  Passau  (Bavaria). 

Found.        0.90          1.20  1.90  36.40       59.60\Analyst :  Cronquist,  Stockholm,  Z.c.  p. 48. 

XII.      0.25  K2O  9.75  H2O  0.5Fe2O3  5.5A12O3  16SiO2/Source  :  Schwarzwald  (Oberpfalz). 
Calcd.         1.30  9.71  4.42  31.05        53.51   \Analyst :  C.  Bischof  (I.  c.  p.  48). 

Found.        1.33         10.50  3.41  30.69        53.10         0.32  MgO       0.26  CaO 


XIII.     12  H2O 
Calcd.      11.19 
Found.     11.14 

5.75  A12O3 
30.39 
30.47 

0.25Fe2O3 
2.07 
1.51 

XIV.     0.5Fe203 
Calcd.         4.38 
Found.        3.54 

5.5  A1203 
30.76 
31.61 

16  SiO2     : 
53.01 
52.32 

XV.      0.5  Fe2O3 
Calcd.        5.54 
Found.       4.22 

4.5  A1,O3 
31.79 
32.00 

12  Si02 
50.20 
51.05 

18  SiO2/Source  :  Klingenberg  a.  M. 
56.34  \Analyst :  unknown  (L  c.  p.  46). 
56.44        0.30  MgO       0.79  CaO       0.30  K2O 

1 2  H2O/ Source  :  Klingenberg  a.  M. 
11.81    \Analyst  :  Vohl,  1875. 
11.81         0.48  CaO 


10  H2O/ Source  :  Klingenberg  a.  M. 
12.47  \ 
12.14       0.46  CaO 


XVI.     0.25  MgO     0.25  CaO     0.25  K2O     9.25  H2O     0.25Fe2O3     5.75A12O3  16SiO2 

Calcd.        0.55              0.77               1.30              9.21               2.21               32.45  53.50 

Found.       0.50              0.50               1.37              9.12               1.50              33.11  54.06 
Source  :  Klingenberg.    Analyst :  C.  Bischof,  1887. 


ULTRAMARINES 


431 


D.  Behaviour  of  Clays,  dried  at  100°  C.,  towards  Sulphuric  Acid,  according 

to  C.  Bischof. 


Number 

HjO 

Kao 

MgO 

FeO 

% 
CaO 

A120, 

Fe203 

SiOa 

Total 

Mo 
H20 

leculai 
K,0 

Eatio 
E,0s 

s 
Si08 

Separated 
SiO»  in 
%       |  Mol. 

Al,0,: 
SiOi  in 
Solution 

1 
2 
3 
4 
5 
6 
7 

9.40 
8.41 
7.44 
10.03 
7.27 
8.14 
15.13 

1.15 
2.09 
2.31 
3.22 
1.21 
1.42 
1.61 

0.20 
0.28 
0.25 
0.45 
0.64 
0.34 
0.85 

0.44 
0.40 
0.21 

0.04 
0.56 
0.06 
0.28 
0.08 
0.10 
0.42 

29.96 
30.34 
25.73 

27.99 
22.30 
27.87 
36.32 

0.45 
0.67 
0.60 
0.44 
0.50 
0.73 
1.00 

58.80 
57.65 
63.61 
56.98 
67.60 
61.19 
44.67 

100 
100 
100 
100 
100 
100 
100 

9.11 
7.83 
4.70 
10.04 
5.41 
8.03 
11.60 

0.31 
0.65 
0.36 
1.01 
0.46 
0.49 
0.75 

5.17 
5.05 
2.91 
5.00 
2.97 
4.93 
5.94 

17 
16 
12 
17 
15 
18 
12 

25.66 
21.35 
36.68 
21.28 
41.87 
26.91 
4.67 

7.42 
5.8 
6.91 
6.34 
9.29 
7.91 
1.26 

5:  10 
5:  10 
6:  10 
5:  11 
6:  10 
5:  10 
6:  11 

Ultramarines. 

Formulae  from  a  series  of  Ultramarine  Analyses. 


1. 

Theory. 
Found. 

Si« 
16.60 
16.45 

Siw 

A112 
16.01 
14.36 

A112 

Na12 
13.64 
14.45 

Na13.5 

S4 
6.32 
6.00 

K0-5 

060 
47.43 

48.74 

S4 

05? 

— 

Total 
100.00 
100.00 

Rickmann,  Dingl.  Journ. 

232, 
164. 

2. 

Theory. 

16.55 

15.96 

15.30 

0.96 

6.31 

44.92 



100.00 

Found. 

16.87 

15.39 

15.66 

0.72 

5.69 

45.67 

— 

100.00 

Philipp,  Ann.   d.  Chem. 

184, 

99 

16.81 

15.27 

15.21 

1.08 

6.42 

45.21 

— 

100.00 

132. 

Si12 

A1M 

Agie 

Na2 

S4 

059 

(H20)4 

3. 

Theory. 

9.39 

9.06 

48.28 

1.29 

3.58 

26.39 

2.01 

100.00 

Found. 

9.78 

9.40 

48.82 

1.07 

3.96 

26.07 

1.90 

100.00 

J.  Szilasi,  Ann.  d.  Chem. 

251, 

M 

8.63 

9.42 

48.79 

1.03 

4.03 

26.29 

1.81 

100.00 

97-114. 

Si12 

A112 

Pb8 

Na2 

S4 

059 

(H20)8 

4. 

Theory. 

9.41 

9.08 

46.16 

1.29 

3.59 

26.44 

4.03 

100.00 

Found. 

9.58 

8.21 

46.02 

0.93 

4.06 

27.27 

3.93 

100.00 

J.  Szilasi,  Ann.  d.  Chem. 

251, 

» 

9.51 

8.16 

46.23 

1.06 

3.94 

27.11 

3.99 

100.00 

97-114. 

Si« 

A112 

Zn8 

Na2 

S4 

059 

(H20)16 

5. 

Theory. 

12.99 

12.53 

20.11 

1.77 

4.95 

36.51 

11.14 

100.00 

Found. 

14.14 

11.80 

19.78 

— 

5.86 

37.52 

10.90 

100.00 

J.  Szilasi,  Ann.  d.  Chem. 

251* 

,, 

14.17 

11.86 

19.98 

0.72 

5.66 

36.51 

11.10 

100.00 

97-114. 

Si12  AI12  Agi,  N&1  S5  O56  K 

6.  Theory.   10.69  10.31  44.67  0.73  5.09  28.51  — 

Found.    10.76      9.90  43.69  0.81  4.89  29.60  0.35 

—  10.54  44.08  0.73  —  —  0.50 


Si12 

7.  Theory.  9.96 
Found.    10.09 
10.09 

',',          10.24 


8.  Theory. 
Found. 


16.86 
16.80 
16.84 


A112 
9.60 
9.00 
9.11 
9.21 
9.23 

A1M 
16.27 
16.32 
16.30 


Ag15 
47.99 
48.08 
47.89 
47.96 
48.66 

Na12 
13.85 
13.94 
13.98 


, 

0.68 
1.15 
1.17 

0.89     — 
—     4.81 


4.73 

4.68 
4.82 


05, 
27.04 
27.00 
26.92 


9.64  43.33  — 
9.70  43.24  — 
9.80  43.08  — 


100.00 

100.00   J.  Philipp    Ber.  d.  D.  chem. 

100.00  Ges.  10,  1227. 


100.00) 

100.00  IK.  Heumann,  Ann.  d.  Chem. 

100.00  |  199,  271. 

—        K.  Heumann,  Ann.  d.  Chem. 
203,  174. 

100.00 

100.00    G.  Guckelberger,  Dingl.  Journ. 

100.00  247,  343,  1883. 


432 


ULTRAMARINES 


Si12 

A112 

Na16 

S4 

0S2 

(H20)2 

Total 

9. 

Theory. 

16.60 

16.01 

18.18 

6.32 

41.11 

1.78 

100.00  \ 

Found. 

16.70 

15.97 

18.48 

7.14 

39.52 

2.19 

100.00 

Jr 

16.76 

15.82 

18.23 

7.20 

39.78 

2.21 

100.00 

tp 

16.73 

15.94 

18.55 

7.22 







» 

17.14 
17.21 

15.87 

18.24 
18.12 

6.92 
7.02 

40.55 

1.18 
1.23 

100~00    J*  Szilasi»  Ann'  d<  Chem-  25X>  97-114. 

,t  • 

16.75 

16.15 

18.08 

6.75 

41.05 

1.22 

ioo!oo 

n 

16.73 

— 

18.12 

6.95 

— 

1.16 

— 

fi 

16.39 

15.08 

18.24 

6.60 

42.16 

1.53 

100.00 

" 

16.45 

15.44 

18.40 

6.80 

41.40 

1.51 

100.  00  ' 

Si12 

Alt, 

Na14 

K 

8, 

050 

10 

Theory. 

17.30 

16.68 

16.59 



8.24 

41.19 

100.00 

Found. 

17.32 

15.94 

16.64 

0.75 

7.91 

41.44 

100.001 

17.51 

15.84 

^ 

j 

7.91 

40.66 

hPhilipp,  Ann.  d.  Chem.  J<*4,132,  1876. 
100.00J 

17. 

08 

t 

18.00 

16.11 

17.05 

— 

8.04 

40.80 

100.00 

t 

18.24 

16.33 





8.36 

40.68 



, 

18.06 

15.78 

17.30 

— 

8.18 

40.68 

100.00  1  Hoffmann's   Analyses,  according  to 

t 

18.11 

16.01 

17.16 



8.05 

40.67 

100.00  [K.  Heumann,  Ann.  d.  Chem.  203,  174, 

18.33 

16.25 

17.14 



8.42 

39.86 

100.00                                                            1880. 

18.20 

16.10 

17.30 



8.40 

40.00 

100.00, 

, 

17.69 

16.13 

17.07 

— 

8.02 

41.09 

100.00)  According  to  K.  Heumann,  Ann.  d. 

. 

17.88 

16.47 

16.61 



7.67 

41.37 

100.00  /                             Chem.  203,  174,  1880. 

•• 

17.77 

16.10 

17.06 

— 

8.02 

41.05 

100.00  K.  Heumann,  Ann.  d.  Chem.  199,  263. 

Si12 

A112 

Na12 

s. 

o« 

11 

Theory. 

18.34 

17.69 

15.07 

6.98 

41.92 



100.00 

Found. 

18.47 

16.88 

15.43 

6.17 

43.05 

— 

100.00    Rickmann,  Dingl.  Journl.  232,  164. 

Si12 

Al]2 

Nau 

s4 

o« 

J2 

Theory. 

17.89 

17.25 

17.14 

6.8*3 

40."9 

— 

100.00 

Found. 

18.00 

17.32 

16.20 

6.62 

41.86 



100.00, 

w 

18.28 

17.15 

16.40 

6.78 

41.39 



100.00 

tt 

18.30 

17.38 

16.10 

6.59 

41.63 

— 

100.00   G.  Guckelberger,  Dingl.  Journ.  247, 

t 

17.98 

17.30 

16.52 

6.88 

41.32 



100.00  f                                                 343,1883. 

•f 

18.08 

17.35 

16.46 

6.69 

41.42 



100.00 

5j 

17.89 

17.43 

16.38 

6.89 

41.41 



100.00J 

M 

18.41 

17.00 

16.40 

6.81 

41.38 

— 

100.00 

» 

18.21 

17.63 

1680 

7.01 

40.35 

— 

100.00 

18.08 

17.32 

17.01 

6.89 

40.70 



100.00 

ff 

18.00 

17.68 

16.92 

7.05 

40.35 

— 

100.00  VG.  Guckelberger    Dingl.  Journ.  247, 

11 

18.90 

17.82 

16.21 

6.40 

40.67 

— 

100.00                                                   386,  1883. 

i 

18.34 

17.60 

16.78 

6.79 

40.49 

— 

100.00 

f 

18.61 

17.12 

16.38 

6.75 

41.14 

— 

100.00  ) 

i 

17.86 
18.09 

17.56 
17.28 

16.60 
17.00 

6.79 
6.90 

41.19 
40.73 

— 

100.00 
100.00  VG.  Guckelberger,  Dingl.  Journ.  247, 

i 

17.29 

16.91 

16.48 

6.60 

41.72 

— 

100.00)                                                 383,  1883. 

Si12 

A112 

Naie 

s4 

o4g 

13 

Theory. 

17.46 

16.84 

19.13 

6.65 

39.92 

— 

100.00 

Found. 

17.35 

16.95 

18.98 

6.70 

4002 

— 

100.00) 

„ 

17.52 

16.84 

18.88 

6.60 

40.16 

— 

100.00  1  G.  Guckelberger,  Dingl.  Journ.  247, 

17.65 

16.50 

18.98 

6.72 

40.15 

— 

100.00)                                                  343,  1883. 

?> 

17.67 

16.40 

19.05 

6.80 

40.08 

— 

100.00) 

w 

17.83 

16.41 

18.97 

6.62 

40.17 

— 

100.00  }-G.  Guckelberger,  Dingl    Journ.  247, 

,} 

18.01 

16.24 

19.20 

6.78 

39.77 



100.00)                                                  383,  1883. 

18.02 

17.00 

18.92 

6.82 

39.24 

— 

100.00    G.  Guckelberger    Dingl.  Journ.  247, 

386,  1883. 

ULTRAMARINES 


433 


14. 

Theory. 

Silf 
14.84 

A1M 
14.31 

Na12 
12.19 

Ag4 
19.08 

5.65 

048 
33.93 

Total 
100.00 

Found. 

15.00 

14.22 

12.50 

19.00 

5.29 

33.99 

100.00 

G.  Guckelberger,  Dingl.  Journ.  247, 

343,  1883. 

Sii, 

Alu 

Na6 

Agio 

S4 

048 

15. 

Theory. 

12.12 

11.68 

4.98 

38.93 

4.61 

27.68 

100.00 

Found. 

12.02 

11.82 

4.58 

39.20 

4.40 

27.98 

100.00 

G.  Guckelberger,  Dingl.  Journ.  247  \ 

347,  1883. 

Sii2 

All. 

Na13.6 

K 

S4 

046 

16. 

Theory. 

18.12 

17.48 

16.75 

1.05 

6.90 

39.70 

100.00 

Found. 

18.29 

16.50 

17.85 

1.33 

6.20 

39.93 

100.00 

H.  Ritter,  Inaug.-Diss.  Gottingen, 

1860. 

e,' 

A  1 

"NTn 

*^M2 

XA.li  o 

IMttjg 

4 

48 

17. 

Theory. 

17.05 

16.45 

21.02 

6.50 

38.98 

— 

100.00 

-  »->• 

Found. 

17.00 

16.60 

21.50 

6.50 

38.40 

— 

100.00 

Rickmann,  Ann.  d.  Chem.  79^,1-22. 

» 

16.74 
16.59 

15.95 
16.14 

20.59 
20.92 

6.22 
5.72 

40.50 
40.63 

— 

100.00 
100.00 

i  Rickmann,  Dingl.  Journ.  232,  164. 

» 

16.53 

16.27 

21.02 

5.51 

40.67 

— 

100.00 

Rickmann,  Dingl.  Journ.  232,  170. 

Sii2 

A112 

Na16 

S4 

046 

18. 

Theory. 

17.75 

17.12 

19.45 

6.77 

38.91 

— 

100.00 

Found. 

18.20 

16.60 

19.00 

6.10 

40.10 

— 

100.00 

R.  Hoffmann,  Ann.  d.  Chem.  194, 

1-22,  1878. 

SiJ6 

A112 

Na14 

So 

O6. 

19. 

Theory. 

18.62 

13.47 

13.38 

11.97 

42.56 

— 

100.00 

Found. 

18.80 

13.00 

13.70 

11.80 

42.70 

— 

100.00 

C.  Griinzweig  per  R.  Hoffmann,  Ann. 

d.  Chem.  194,  18. 

Siie 

A112 

Naie 

K 

S9 

065 

20. 

Theory. 

18.15 

13.13 

14.91 

— 

11.67 

42.14 

100.00 

Found. 

17.29 

12.55 

14.66 

11.38 

44.12 

100.00 

Philipp,  Ann.  d.  Chem.  7^,132,1876. 

» 

17.57 

12.54 

14.51 

0.80 

11.38 

43.20 

100.00 

Si12 

A16 

Na9 

Se 

088 

21. 

Theory. 

23.40 

11.28 

9.61 

13.37 

42.34 



100.00 

Found. 

23.12 

11.71 

8.97 

13.22 

42.98 

— 

100.00 

G.  Scheffer,  Ber.  d.  D.  Chem.  Ges. 

1451,  1873. 

Siio 

A16 

Na0 

g 

034 

22. 

Theory. 

20.77 

12.02 

10.24 

14.24 

42.73 



100.00 

Found. 

21.63 

12.33 

9.93 

13.96 

42.15 

— 

100.00 

G.  Scheffer,  Ber.  d.  D.  Chem.  Ges. 

1451,  1873. 

Siie 

A112 

Na20 

Sic 

062 

23. 

Theory. 

17.61 

12.74 

18.08 

12.58 

38.99 



100.00 

Found. 

17.70 

13.80 

17.70 

12.20 

38.60 



100.00 

R.  Hoffmann,  Ann.  d.  Chem.  194, 

14.  1878. 

24.  Theory. 

Siis 
20.34 

A1M 
13.08 

Na14 
12.99 

15™  Q 

38.09 

100.00 

Found. 

20.20 

13.50 

12.90 

15.50 

37.09 



100.00 

R.  Hoffmann,  Ann.  d.  Chem.  194, 

17,  1878. 

Siw 

A112 

Na18 

Sl2 

08i 

25. 

Theory. 

19.37 

12.45 

15.91 

1476 

37.51 



100.00 

Found. 

19.20 

12.60 

16.50 

14.20 

37.50 

— 

100.00 

19.00 

12.70 

16.80 

14.00 

37.50 



100.00 

19.00 
19.30 
19.30 

13.00 
12.50 
12.80 

16.50 
16.80 
16.10 

13.80 
13.90 
14.00 

37.70 
37.50 
37.80 

— 

100.00 
100.00 
100.00 

G.  Guckelberger,  Dingl.  Journ.  247  , 
343,  1883. 

19.00 

13.00 

15.90 

14.00 

38.10 

— 

100.00 

26. 

Theory. 

18*92 

All. 
12.17 

Na20 
17.27 

1S4'.42 

062 
37.22 

100.00 

Found. 

19.00 

12.70 

17.40 

13.60 

37.30 

— 

100.00 

R.   Hoffmann,   Dingl.   Journ.   247, 

1883  ;  Ann.  d.  Chem.  194,  14. 

Siie 

A112 

Na12 

S12 

059 

27. 

Theory. 

19.00 

13.74 

13.66 

16.28 

37.32 

— 

100.00 

Found. 

18.80 

13.80 

14.10 

16.30 

37.00 

— 

100.00 

R.  Hoffmann,  Ann.  d.  Chem.  794,  17, 

2  F 


434 


PORTLAND  CEMENTS 


Si 

A16 

Na8 

S6 

036 

Total 

28.  Theory. 

23.117 

11.18 

12.69 

13.24 

39.72 

100.00 

Found. 

23.04 
23.63 

10.77 
11.09 

11.90 
12.00 

14.02 
13.46 

40.27 
39.82 

100.00  | 
100.00  » 

G.  Scheffer,  Ber.  d.  D.  chem.  Ges.  1451,  1873 

Si 

A112 

Na16 

S6 

060 

29. 

Theory. 
Found. 

2L47 
21.53 

13.79 
13.42 

15.68 
15.38 

8.18 
9.25 

40.88 
40.42 

100.00 
100.00 

E.  Btichner,  Ber.  d.  D.  chem.  Ges.  7,  989,  1874 

Si 

A112 

Na18 

S5 

062 

30. 

Theory. 

21.  ^5 

13.55 

17.29 

6.68 

41.43 

100.00 

Found. 

20.75 

13.53 

17.01 

6.78 

41.93 

100.00  \ 

21.00 

13.08 

16.98 

6.79 

42.15 

100.00 

| 

" 

20.89 
20.51 

13.28 
13.50 

17.28 
18.00 

6.80 
6.90 

41.75 
41.09 

100.00  ! 

100.00  | 

>G.  Guckelberger,  Dingl.  Journ.  247,  343,  1883, 

21.00 

13.12 

17.80 

7.02 

41.06 

100.00 

| 

99 

20.69 

13.30 

17.20 

6.90 

41.91 

100.00  ; 

Portland  Cements 

Formulae  of  a  Series  from  Analyses  of  Portland  Cements 


SiO, 

Al40a 

Fe,03 

CaO 

MgO  K,0 

Na,0 

CO, 

SOa 

H20     Total 

1.  Theory. 
Found. 

25.34 
25.29 

5.37 
5.41 

8.39 
8.64 

50.891.39 
50.401.24 

0.82 
0.50 

0.544.61 
0.734.61 

1.39 
1.10 

1.26 
1.30 

100.00 
99.92 

Feichtinger,  Dingl.  Journ.,  40-6] 

108-118,  185(. 

2.  Theory. 

24.09 

6.83 

5.35 

63.73  — 

— 

— 

— 

— 

— 

100.00 

Found. 

24.30 

6.90 

4.8064.10 

— 

— 

— 

—  ' 

— 

— 

100.10 

)  A.  W.  Hoffmann,  Amtl.  Ber.  c 

3.  Theory. 

23.65 

6.70 

5.2664.39 

— 

— 

— 

— 

— 

— 

100.00 

f         Wien.  Ausst.  3,  I,  583,  1871 

Found. 

23.30 

6.50 

4.7065.40 

— 

— 

— 

— 

— 

— 

99.90 

) 

4.  Theory. 

22.78 

6.45 

5.06 

63.78 

0.67 







1.26 



100.00 

Found. 

22.48 

6.52 

4.46 

62.931.48 





— 

1.39 

— 

99.26 

K.  Pietrusky,  J.  B.  T.  48,  1,  474 

99 

21.94 

6.02 

4.38 

64.63 

1.25 

— 

— 

— 

1.12 

— 

99.34 

Chem.  Ind.  190; 

23.44 

6.35 

3.99 

63.21 

1.16 

— 

— 

— 

1.22 

— 

99.36 

5.  Theory. 

22.50 

6.38 

5.00 

63.00 

1.88 



— 

— 

1.24 

— 

100.00 

Found. 

22.00 

6.50 

3.2062.10 

2.10 

— 

— 

— 

1.10 

— 

97.00 

J.  B.  T.  43,  765. 

22.42 

6.28 

3.6262.82 

2.09 







1.29 



98.52 

99 

22.10 

6.25 

3.7062.50 

1.75 

— 

— 

— 

1.20 

— 

97.50 

22.07 

6.59 

3.41 

62.00 

1.04 

— 

— 

— 

1.53 

— 

96.64 

6.  Theory. 

22.59 

6.36,  4.98 

63.26 

1.56 

— 

— 

1.25 

— 

100.00 

Found. 

22.48 

6.52 

4.4662.93 

1.48 



— 

— 

1.30 

— 

99.17 

Tonind.-Ztg.,  1826,  1901. 

>» 

23.44 

6.35 

3.99 

63.21 

1.15 

— 

— 

1.22 

— 

99.36 

7.  Theory 

22.30 

7.06 

3.69 

62.02 

2.46 

— 

— 

2.46 

100.00 

Found. 

21.86 

7.17 

3.73 

61.14 

2.34 

— 

— 

1.94 

— 

98.18 

Tonind.-Ztg.,  1826,  1901. 

8.  Theory 

22.22 

7.03 

3.67 

65.23 

0.61 

— 

— 

— 

1.23 

— 

100.00 

Found. 

22.10 

6.40 

3.04 

65.44 

0.81 

— 

— 

— 

1.61 

— 

99.40 

Tonind.-Ztg.,  2015,  1901. 

9.  Theory 

21.83 

6.13 

4.82 

64.50 

1.51 





— 

1.21 



100.00 

Found. 

21.94 

6.02 

4.38 

64.62 

1.25 

— 

— 

1.12 

— 

99.33 

10.  Theory 

21.55 

7.58 

2.38 

64.93 

1.19 





2.37 



100.00 

Found. 

21.26 

7.64 

2.86 

63.7411.10 

— 

— 

2.18 

0.60 

99.38 

Tonind.-Ztg.,  2015,  1901. 

11.  Theory. 

23.71 

12.10 

— 

64.19  — 



___ 



__ 



100.00 

Found. 

23.80 

11.40 

— 

64.80  — 





— 





100.00 

A.  W.  Hoffmann,  Amtl.  Ber.  < 

12.  Theory. 

21.17 

8.04 

4.20 

61.82  3.50  —,— 





1.27 

100.00 

Wien.  Ausst.  3,  I,  583,  187 

Found. 

20.72 

7.57 

4.48 

60.523.02      1.02 

0.52 

0.37 

1.22 

99.44 

Fischer,  H.  d.  ch.  T.  828. 

13.  Theory. 

20.64 

7.89 

4.13 

62.59  2.06  1.62 

1.07 

— 

— 



100.00 

Found. 

20.33    8.67 

3.80,62.33  2.48  1.20 

0.85 







99.66 

J.  B.  T.  43,  732. 

,, 

20.33 

7.19 

3.6563.65|2.62 

1.04 

0.80 

— 

— 

— 

99.28 

14.  Theory. 

24.16 

— 

10.7365.12!  — 







___ 

__ 

100.00 

Found. 

23.80 

— 

11.40 

64.80 

—  ._._ 

— 







.  

100.00 

A.  W.  Hoffmann,  Amtl.  Ber.   < 

Wien.  Ausst.  J,  I,  583,  187, 

PORTLAND   CEMENTS 


435 


SiO, 

Al,0, 

FeaO, 

CaO 

MgO 

K,O 

Na,0 

CO, 

SO, 

Hao 

Total 

15.  Theory. 

23.65 

5.02 

2.63 

65.87 

1.09 

_^  .  j- 



.74 



100.00 

Found. 

23.40 

5.18 

2.79 

65.80 

1.13 

0.48 

— 

.42 

— 

100.20 

Loebell,  J.  B.  T.   48,  1, 

„ 

32.68 

5.03 

2.82 

65.47 

1.08 

0.53 

— 

.36 

— 

99.97 

466. 

16.  Theory. 

32.52 

7.37 

5.79 

44.56 

1.45 

0.85 

0.57 

4.78 

.46 

0.66 

100.00 

Found. 

32.60 

7.17 

6.23 

44.96 

1.52 

0.45 

0.64 

4.52 

.20 

0.72 

100.00 

Fehling,  H.  d.  Chem.  482, 

17.  Theory. 

34.15 

7.73 

6.06 

46.76 

0.76 

— 

— 

1.66 

.51 

1.37 

100.00 

1875. 

Found. 

34.07 

7.49 

5.58 

46.07 

0.90 

— 

— 

1.38 

.96 

1.47 

98.92 

Fehling,  H.  d.  Chem.  482, 

18.  Theory. 

32.63 

7.34 

5.76 

45.37 

1.44 

0.85 

0.56 

3.96 

.44 

0.65 

100.00 

1875. 

Found. 

32.60 

7.17 

6.23 

44.96 

1.52 

0.45 

0.64 

4.52 

.20 

0.72 

100.01 

Feichtinger,  Dingl.  Jour. 

19.  Theory. 

34.08 

7.67 

6.02 

46.33 

0.75 

0.88 

0.58 

0.82 

.50 

1.35 

100.00 

40-61,  108-118,  1859. 

Found. 

34.07 

7.49 

5.58 

46.07 

0.90 

0.27 

0.56 

1.38 

.96 

1.47 

99.75 

Feichtinger,  Dingl.  Jour. 

20.  Theory. 

29.33 

4.95 

7.72 

48.01 

1.94 

0.05 

0.50 

5.69 

0.65 

1.16 

100.00 

40-61,  108-118,  1859. 

Found. 

28.56 

4.75 

8.14 

47.53 

2.04 

0.48 

0.68 

5.58 

0.40 

1.20 

99.36 

Feichtinger,  Dingl.  Jour. 

21.  Theory. 

28.89 

4.92 

7.71 

48.47 

1.93 

0.76 

0.50 

5.66 

— 

1.16 

100.00 

40-61,  108-118,  1859. 

Found. 

28.56 

4.75 

8.14 

47.53 

2.04 

0.48 

0.60 

5.58 

— 

1.20 

98.88 

Fehling,  H.  d.  Chem.  482, 

22.  Theory. 

25.39 

7.19 

2.26 

56.87 

2.82 

1.33 

0.87 

1.00  MnO 

2.27 



100.00 

1875. 

Found. 

24.26 

6.97 

2.88 

56.90 

2.15 

0.90 

0.54 

1.60  MnO 

1.28 

— 

97.48 

J.  B.  T.  44,  749. 

24.  Theory. 

23.35 

6.57 

2.06 

64.93 

1.03 

— 

— 

— 

2.06 

— 

100.00 

Found. 

22.96 

6.78 

2.54 

63.95 

0.98 

— 

— 

— 

1.96 

— 

99.17 

Tonind.-Ztg.  2015,  1901. 

25.  Theory. 

23.19 

5.87 

3.06 

63.03 

1.02 

0.60 

1.19 

2.04 

— 

100.00 

Found. 

23.40 

6.07 

2.51 

63.870.97 

0.80 

1.22 

— 

1.45 

— 

100.29 

v.  Teichek,   Chem.  Ind. 

26.  Theory. 

23.21 

5.92 

3.09 

65.72 

1.03 







1.30 



100.00 

24,  445,  1901. 

Found. 

22.71 

6.42 

2.81 

63.14 

1.04 

1.64  CaSO4 

O.SOCaCO., 

— 

— 

93.56 

Tonind.-Ztg.  409,  1879. 

27.  Theory. 

22.94 

5.81 

3.03 

65.18 

1.02 

— 



2.02 

— 

100.00 

Found. 

22.33 

5.53 

3.28 

64.40 

1.20 

— 

— 

2.41 

— 

99.15 

Tonind.-Ztg.  2015,  1901. 

28.  Theory. 

10.39 

7.37 

2.31 

71.96 

3.47 

—  . 

1.91 

— 

2.59 

100.00 

Found. 

10.38 

6.66 

1.99 

72.10 

3.27 

0.85 

1.64 

0.43 

2.56 

99.88 

Fischer,  H.  d.  ch.  T.  828. 

29.  Theory. 

25.29 

8.35 

9.36 

52.43 

— 

0.72 

2.06 

0.94 

0.85 

100.00 

Found. 

25.21 

8.26 

8.35 

52.46 

— 

0.78 

2.25 

1.30 

0.68 

99.29 

Fehling,  H.  d.  Ch.  482, 

30.  Theory. 

25.13 

8.25 

9.24 

52.42 

0.46 

— 

0.71 

2.03 

0.92 

0.83 

100.00 

1875. 

Found. 

25.21 

8.26 

8.35 

52.46 

0.50 

0.30 

0.78 

2.25 

1.30 

0.68 

100.09 

Feichtinger,  Dingl.  Jour. 

31.  Theory. 

17.25 

8.18 

2.57 

63.71 

3.85 

_>_._|_^ 

2.12 



2.32 

100.00 

40-61,  108-118,  1859. 

Found. 

16.75 

7.97 

2.71 

61.92 

4.03 

1.25 

2.42 

0.42 

2.24 

94.64 

Fischer,  H.  d.  ch.  T.  828. 

32.  Theory. 

17.71 

8.37 

2.62 

66.12 

3.28 

^~~~~~~-^ 

0.72 

— 

1.18 

100.00 

Found. 

17.04 

8.09 

3.25 

65.05 

3.04 

0.92 

0.83 

0.30 

1.06 

99.58 

Fischer,  H.  d.  ch.  T.  828. 

33.  Theory. 

15.00 

7.03 

2.20 

66.44 

4.41 

;  x 

2.42 

— 

2.50 

100.00 

Found. 

14.76 

7.52 

2.15 

65.42 

3.89 

0.86 

2.19 

0.52 

2.32 

99.63 

Fischer,  H.  d  ch.  T.  828. 

34.  Theory. 

21.78 

13.89 

— 

45.06 

3.18 





2.00 

1.83 

12.26 

100.00 

Found.  |21.02 

13.02 

— 

43.57 

3.09 

— 

— 

1.76 

2.29 

11.87 

96.62 

J.  B.  T.  44,  745. 

35.  Theory. 

20.59 

13.04 

— 

42.64 

2.77 

1.01 

0.66 

1.40 

2.55 

13.82 

98.48 

Found. 

20.22 

14.52 

— 

41.87 

3.02 

077 

0.71 

1.86 

3.02 

13.77 

99.76 

Zulkowski. 

36.  Theory. 

24.59 

15.68 

0.91  MnO 

48.77 

3.08 

2.41 

1.59 

0.92  FeO 

2.05 



100.00 

t  2jU.lo\vski 

Found. 

24.64 

15.27 

0.82MnO 

49.70 

3.29 

1.67 

1.37 

1.12  FeO 

1.72 

— 

99.60 

1  J.  B.  T.  44,  745. 

37.  Theory. 

21.04ll3.32 

0.78  FeO 

43.57 

2.83 

1.02 

1.35 

0.96 

2.61 

11.75 

100.00 

0.77  MnO. 

Found'. 

21.02  13.02 

0.85  FeO 

43.57 

3.090.31 

0.84 

1.76 

2.29 

11.87 

99.28 

0.66  MnO  Zulkowski. 

436 


PORTLAND   CEMENTS 




SiO, 

AI.O, 

Fe20, 

CaO  |MgO 

KaO  |Na,0 

CO, 

so, 

H20 

Total 

38.  Theory. 
Found. 

24.73 
24.64 

15.65 
15.27 

0.92  FeO 
1.12  FeO 

49.77|3.32 
49.703.29 

1.80 
1.67 

1.59 
1.37 

0.281.03 
0.5411.72 

0.9  iMnO  100.00 
0.82MnO  100.14 

Zulkowski 

39.  Theory. 
Found. 

pf 

23.71 
22.23 
23.72 

7.78 
7.75 
7.36 

5.23 
5.30 
5.50 

54.370.87 
54.100.75 
54.400.86 

1.02 
1.10 
0.86 

2.03 
1.66 
1.78 

3.14 
2.15 

2.80 

0.87 
1.00 
1.12 

0.98 
1.00 
0.96 

100.00 
97.04 
99.36 

Feichtinger,   Dingl.  Journ 
40-61,  108-118,  1859 

40.  Theory. 
Found. 

23.64 
22.47 

8.93 
7.81 

3.51 
3.42 

61.29 
61.13 

0.87 
1.06 

— 

— 

z 

1.76 
2.03 

_ 

100.00 
97.92 

J.  B.  T.  35,  852.' 

23.57 

8.89 

3.51 

60.10 

0.95 

— 

— 

— 

0.90 

— 

97.92 

» 

22.96 

9.14 

3.23 

61.19 

1.03 

— 

— 

— 

1.45 

— 

99.00 

M 

23.36 

8.12 

3.21 

60.57 

1.19 

— 

— 

— 

1.81 

— 

98.26 

41.  Theory. 
Found. 
» 

28.72 
28.54 
29.08 

3.05 
3.43 
3.40 

1.59 
1.13 
1.24 

65.85 
66.62 
66.07 

0.79 
0.30 
0.20 

E 

— 

— 

E 

E 

100.00 
100.02 
99.99 

Tonind.-Ztg.  981,  1902. 

42.  Theory. 

27.39 

2.92 

1.52 

68.17 

— 

100.00 

Found. 

27.06 

3.19 

1.29 

68.06 

0.35 

— 

— 

— 

— 

— 

99.95 

43.  Theory. 

26.49 

3.75 

— 

69.03 

0.73 

— 

— 

— 

— 

— 

100.00 

Found. 

26.30 

3.50 

0.77 

68.84 

0.54 

— 

— 

— 

— 

— 

99.95 

44.  Theory. 
Found. 

23.96 
23.75 

3.38 
3.11 

0.85 

72.66 
72.01 

.^  _ 

100.00 
100.02 

0.30 

— 

— 

— 

— 

REFERENCES  TO  ANALYSES 

Topazes. 

1,  Berzelius,  Abhandl.  </,  247  ;  Schweigg.  Journ.  16,  423.  2,  Berzelius,  I.  c.  3, 
Berzelius,  I.  c.  4,  Rammelsberg,  Berl.  Akad.  1865,  264.  5,  Hildebrand,  Geol.  Survey 
Bull.  No.  20.  6,  Klemm,  Beitr.  z.  Kenntnis.  des  Topas,  Inaug.-Diss.,  Jena  1873,  12. 
7,  Klemm,  1.  c.  8,  Klemm,  I.  c.  9,  10-13,  Klemm,  I.  c.  14,  Sommerland  quoted  by  v. 
Groddeck,  Zeitschr.  d.  Geol.  Ges.  1884,  36,  642.  15,  Ranmelsberg,  I.e.  16-18, 
Rammelsberg,  I.  c. 

Epidotes. 

1,  Nanke  per  Bauer,  N.  Jahrb.  1880,  2,  81.  2,  Stockar-Escher,  Pogg.  Ann.  95, 
501.  3-6,  Stockar-Escher,  I.  c.  7,  Wilk,  Groths  Zeitschr.  12,  517.  8,  9,  Stockar- 
Escher,  I.  c.  10,  F.  Heddle,  Min.  Soc.,  London  1879,  3,  18.  11,  Scheerer,  Pogg.  Ann. 
95,  501.  12,  Richter,  Pogg.  Ann.  95,  501.  13,  Hermann,  Erdm.  Journ.  Chem.  43,  88. 
14,  A.  G.  Dana,  Groths  Zeitschr.  Jo,  490.  15,  Mauthner,  Tscherm.  Mitt.  1872,  259. 
16,  Laspeyres,  Groths  Zeitschr.  3,  564.  17,  Renard,  Groths  Zeitschr.  6,  177.  18, 
Hermann,  Erdm.  Journ.  43,  81.  19,  v.  Drasche  per  Klein,  N.  Jahrb.  1872,  120.  20, 
Ludwig,  Groths  Zeitschr.  6,  180.  21,  Ludwig,  Tscherm.  Mitt.  1872,  194.  22,  Las- 
peyres, Groths  Zeitschr.  3,  564.  23,  Wulf,  Tscherm.  Mitt.  N.  F.  8,  235.  24,  Rammels- 
berg, Zeitschr.  d.  Geol.  Ges.  24,  650.  25,  Scheerer,  Pogg.  Ann.  95,  501.  26,  Scheerer, 
/.  c.  27,  Stockar-Escher,  Pogg.  Ann.  95,  501.  28,  Rammelsberg,  Pogg.  Ann.  76,  93. 
29,  Scheerer,  Pogg.  Ann.  95,  501. 

Mesolites. 

1,  Thomson,  Edinb.  N.  Phil.  Journ.  1834,  17,  186  ;  Outl.  Min.  1836,  326,  328.  2, 
Luedecke,  N.  Jahrb.  1881,  2,  33.  3,  Marsh  quoted  by  Dana,  Min.  1868,  431.  4,  Thomson 
Edin.  N.  Phil.  Journ.  1834,  17,  186.  5,  Thomson,  Ed.  N.  Phil.  Journ.  1834,  17,  186. 
6,  E.  E.  Schmid,  Pogg.  Ann.  1871,  142,  121.  7,  Breidenstein  quoted  by  Rammelsberg, 
Mineralch.,  5.  Suppl.,  1853,  168.  8,  Riegel,  Journ.  f.  prakt.  Chem.  1847,  40,  319. 
9,  Fuchs  &  Gehlen,  Schweigg.  Journ.  1816,  18,  1.  10,  Heddle,  Phil.  Mag.  1857,  13, 
148.  11,  Heddle,  ibid.  12-14,  Heddle,  Phil.  Mag.  1857,  13,  50,  148.  15,  Berzelius, 
Jahresber.  1823,  j,  147.  16,  Heddle,  Phil.  Mag.  1857,  13,  50.  17,  Fuchs  &  Gehlen, 
Schweigg.  Journ.  1816,  18,  1.  18,  Durscher,  Ann.  mines  1841,  19,  578.  19,  E.  E. 
Schmid,  Pogg.  Ann.  1871,  142,  121.  20,  Sart.  v.  Waltershausen,  Vulk.  Gest.  1853, 
267.  21,  Fuchs  &  Gehlen,  Schweigg.  Journ.  1816,  18.  1.  22,  Fuchs  &  Gehlen,  ibid. 
23,  E.  E.  Schmid,  Pogg.  Ann.  1871,  142,  121.  24,  Lemberg,  Zeitschr.  d.  Geol.  Ges. 
1876,  28,  552.  25,  How,  Am.  Journ.  Sc.  1858,  26,  32.  26,  How,  ibid.  27,  Marsh 
quoted  by  Dana,  Min.  1868,  431.  28,  Darapsky,  N.  Jahrb.  1888,  i,  66.  29,  Sadtler, 
Am.  Chem.  Journ.  1883,  4,  357. 

The  Glintonite  Group. 

1,  Kobell,  Journ.  f.  prakt.  Chem.  1853,  58,  39.  2,  Hunt,  Am.  Journ.  Sc.  1861,  31, 
442.  3,  Damour,  Bull.  soc.  min.,  Paris  1884,  7,  84.  4,  Hermann,  Journ.  f.  prakt. 
Chem.  1851,  53,  13.  5,  Suida  per  Tschermak,  Groths  Zeitschr.  3,  5,  11.  6,  Heddle, 
Groths  Zeitschr.  5,  618.  7,  Delesse,  Compt.  rend.  1846,  22,  595  ;  Ann.  mines  1846, 
jo,  232.  8,  Erdmann,  Journ.  f.  prakt.  Chem.  1834,  4,  127  ;  6,  89.  9,  L.  Smith,  Ann. 
mines  1850, 18,  300.  10,  Renard,  Bull.  soc.  min.,  Paris  1884,  7,  42.  11,  Damour,  Bull, 
soc.  min.,  Paris  1884,  7,  84.  12,  SipQcz,  Groths  Zeitschr.  3,  508.  13,  L.  Smith,  Ann. 
minea  1850,  18,  300.  14,  L.  Smith,  ibid.  15,  F.  Heddle,  Groths  Zeitschr.  5,  618. 
16,  Kobell,  Journ.  f.  prakt.  Chem.  1853,  58,  40.  17,  Renard,  Groths  Zeitschr.  8,  420. 
18,  Jackson,  Rep.  geol.  R.  1840,  I,  88.  19,  Damour,  Bull.  soc.  min.,  Paris  1879,  2, 

437 


438          REFERENCES  TO  ANALYSES 

167.  20,  Damour,  Ann.  mines  1842,  2,  357.  21,  Damour,  ibid.  22,  Sipocz,  Groths 
Zeitschr.  3,  502.  23,  Hermann,  Journ.  f.  prakt.  Chem.  1851,  53,  13.  24,  Whitney, 
Proc.  nat.  hist,  soc.,  Bost.  1849,  100.  25,  Wagner  per  Knop,  N.  Jahrb.  1872,  788. 
26,  O.  Schiefferdecker  per  Knop,  N.  Jahrb.  1872,  788.  27,  v.  Foullon,  Jahrb.  geol. 
Reichsanst.,  Wien  1833,  33,  326.  28,  SchrSder,  Erlaut.  Sect.  Zwota  1884,  3.  29, 
Bonsdorff  quoted  by  G.  Rose,  Reise  1837,  j,  253. 

Micas. 

1,  Pisani,  Compt.  rend.  1876,  83,  166.  2,  Genth,  Groths  Zeitschr.  2,  10.  3,  Rumpf, 
Tscherm.  Mitt.  1874,  177.  4,  Crawe,  Am.  Journ.  Sc.  1850,  10,  383.  5,  Thomson, 
Outl.  Min.  1836,  i,  373.  6,  Bromeis,  Pogg.  Ann.  1842,  55,  112.  7,  Igelstrom,  N. 
Jahrb.  1872,  296.  8,  Chatard,  Amer.  Journ.  Sc.  1888,  36,  263.  9,  Cohen,  Groths 
Zeitschr.  7,  405.  10.  v.  Ammon  quoted  by  v.  Giimbel,  Geogn.  Beschr.  d.  Fichtelgebirges 
1879,  182.  11,  Chatard  quoted  by  Genth,  Amer.  Phil.  Soc.,  19  Sept.  1873,  26.  12, 
Hilger,  N.  Jahrb.  1879,  129.  13,  Knop,  N.  Jahrb.  1859,  560.  14,  Baltzer,  N.  Jahrb. 
1872,  654.  15,  Konig  quoted  by  Genth,  Amer.  Phil.  Soc.,  19  Sept.  1873,  32.  16, 
Konig,  Proc.  Nat.  Sc.,  Philadelphia  1877,  269.  17,  Chatard,  Amer.  Phil.  Soc.,  19 
Sept.  1873,  44.  18,  Schwager,  N.  Jahrb.  1878,  385.  19,  Knop,  N.  Jahrb.  1861,  150. 

20,  Thoreld,  Act.  Soc.  Fenn  3,  815  ;    A.  Nordenskiold,  Beskrifn.  Finl.  Min.  1855,  146. 

21,  Muller  quoted  by  Breithaupt,  Min.  Stud.  1866,  33.     22,  Kobell,  Kaetn.  Arch.  Nat. 
12,  29.     23,  Zellner,  Tscherm.  Mitt.  1873,  129.     24,  Crossley  quoted  by  Jackson,  Sillim. 
Amer.  Journ.   1850,  9,  422.     25,  Genth,  Amer.  Phil.  Soc.,   19  Sept.   1873,   29.     26, 
Sharpless,  Amer.  Journ.  Sc.  1869,  47,  319.     27,  Smith,  Amer.  Journ.  Sc.  1851,  n,  59. 
28,  Smith  &  Brush,  Amer.  Journ.  Sc.  1853,  15,  209.     29-31,  Smith  &  Brush,  ibid. 
32,  Massalin,  Trommsd.  N.  J.  4,  2,  324.     33,  Rammelsberg,  Zeitschr.  d.  Geol.  Ges. 
1862,  14,  761.     34,  Lemberg,  Zeitschr.  d.  Geol.  Ges.  1888,  40,  656.     35,  Genth,  Amer. 
Phil.  Soc.,  19  Sept.  1873,  26.     36,  Konig  quoted  by  Genth,  ibid.     37,  Sauer,  Zeitschr. 
d.  Geol.  Ges.  1885,  37.  460.     38,  Cossa,  Accad.  Torino,  Dec.  1874,  Ric.  chim.  e  microscop. 
1881,  75.     39,  Cossa,  ibid.     40,  Konig,  Amer.  Phil.  Soc.,  19  Sept.  1873,  26.     41,  Delesse, 
Ann.  chim.  phys.   1845,  15,  248.     42,  Blau,  Tscherm.  Mitt.   1873,  32.     43,  Sipocz, 
Tscherm.  Mitt.  1873,  31.     44,  Igelstrom,  Berg-  u.  Hiittenm.  Ztg.  25,  308.     45,  Chatard 
quoted  by  Gill,  Johns  Hopkins  Univ.  Circ.,  No.  75.     46,  Dewey,  Groths  Zeitschr.  5,  210. 
47,  Mallet,  Rammelsbergs  Mineralchemie,  5.  Suppl.,  1853,  148.     48,  Kjerulf,  Erdm. 
Journ.  f.  prakt.  Chem.  1855,  65,  191.     49,  Riepe  quoted  by  G.  v.  Rath,  Sitzb.  Niederrhein. 
Ges.,  Bonn  1879,  383.     50,  Lehnut,  Thomsons  Min.  1836,  i,  330.     51,  Blythe,  ibid. 
52,  Scheerer,  Zeitschr.  d.  Geol.  Ges.  1862,  14,  63.     53,  Killing  quoted  by  Sandberger, 
Erzgange,  Wiesbaden  1882,  1.  Heft ;  Groths  Zeitschr.  7,  411.     54,  Laspeyres,  Tscherm. 
Mitt.  1873,  147.     55,  Cossa,  Accad.  Torino,  Dec.  1874 ;   Ric.  chim.  e  microscop.  1881, 
75.     56,  Varrentrapp,  Pogg.  Ann.  1844,  61,  381.     57,  Brush,  Amer.  Journ.  Sc.  1861, 
31,  369.     58,  Chatard,  Amer.  Phil.  Soc.,  19.  Sept.   1873,  32.     59,  Killing  quoted  by 
Rammelsberg,  Monatsber.  Akad.,  Berlin  1879,  845.     60,  Pisani,  Compt.  rend.  1862, 
54,  686.     61,  Cooke,  Proc.  Amer.  Acad.  Arts  1874,  35.     62,  Chatard,  Amer.  Phil.  Soc., 
19  Sept.  1873,  44.      63,  Konig,  Amer.  Phil.  Soc.,  19  Sept.  1873,  32.      64,  C.  v.  Hauer, 
Kenngott,  Min.  Forsch.  1856,  80.     65,  Ficinus,  Schweigg.  Journ.  1819,  26,  280.     66, 
Galbrath,  Journ.  Geol.  Soc.  Dublin  6,  165.     67,  Galbrath,  ibid.     68,  Kobell,  Journ.  f. 
prakt.   Chem.   2,   295.     69,  Muller  quoted  by  Breithaupt,  Min.   Stud.    1866,   36.     70, 
Bromeis  quoted  by  Bischof,  Lehrb.  Geol.  2,  1418.     71,  Konig,  Proc.  Nat.  Sc.,  Philad. 
1877,  269.     72,  C.  v.  Hauer,  Sitzber.  Akad.,  Wien  1853,  n,  609.     73,  Bromeis,  Pogg. 
Ann.  1842,  55,  112.     74,  Jewreinow,  Pogg.  Ann.  1847,  70,  854.     75,  Konig  quoted  by 
Genth,  Amer.  Phil.  Soc.,  19  Sept.  1873,  37.     76,  K6nig,  ibid.     77,  Renard,  Bull.  Acad. 
Belg.  1881,  2,  Nr.  9.     78,  Roepper  quoted  by  Sharpless,  Amer.  Journ.  Sc.  1869,  47,  319. 
79,  Boricky  quoted  by  v.  Zepharovich,  Sitzber.  Akad.  Wien  54,  287.     80,  Haughton, 
Phil.  Mag.  1855,  9,  272.     81,  Heddle,  Groths  Zeitschr.  5,  627.     82,  Heddle,  Groths 
Zeitschr.  5,  617,  618,  627.     83,  Delesse,  Ann.  mines  1849,  16,  202.     84,  Schafhautl, 
Ann.  chem.  Pharm.  1843,  46,  325.     85,  Rammelsberg,  Zeitschr.  d.  Geol.  Ges.  1862,  14, 
763.     86,  Rammelsberg,  Glimmer,  Berlin  1889,  67. 

Scapolites. 

1,  Crossley,  Phil.  Mag.  1850,  37,  179.  2,  Rammelsberg,  Ak.  Berl.  1885,  605.  3, 
Wolff,  Inaug.-Diss.,  Berl.  1843  ;  N.  Jahrb.  1846,  334.  4,  Damour,  Institut  1862,  21. 
5,  G.  v.  Rath,  Pogg.  Ann.  1853,  90,  88.  6,  Hunt,  Amer.  Journ.  Sc.  1849,  8,  103.  7, 
Hermann,  Journ.  f.  prakt.  Chem.  1851,  54,  410.  8,  Crossley,  Phil.  Mag.  1850,  37,  179. 


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Jahrb.  1881,  Beil.-Bd.  j,  225.  13,  Lemberg,  Zeitschr.  d.  Geol.  Ges.  1887,  39,  572. 
14,  G.  v.  Rath,  Zeitschr.  d.  Geol.  Ges.  1866, 18,  636.  15,  Pisani  quoted  by  Des  Cloizeaux, 
Min.  1862,  225,  234.  16,  Lagus  &  Olkkonen  per  Wilk,  Groths  Zeitschr.  7,  110.  17, 
Berkley  quoted  by  Dunnington,  Amer.  Chem.  Journ.  1892,  620.  18,  Wolff,  Diss., 
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Tscherm.  Mitt.  N.  F.  4,  266.  26,  F.  Heddle,  Min.  Soc.  London  1882,  5,  19.  27,  N. 
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1895,  456.  31,  Wilk,  Min.-Samml.,  Helsingf.  1887,  39  ;  Groths  Zeitschr.  n,  312. 
32,  N.  Nordenskjold,  Schweigg,  Journ.  1821,  31,  417.  33,  Hartwall  &  Herdberg, 
Berzel.  Jahresb.  4,  155.  34,  Hunt,  Amer.  Journ.  1855,  19,  428;  Rep.  Geol.  Can. 
1853,  1863,  483.  35,  Hermann,  Journ.  f.  prakt.  Chem.  1851,  54,  177.  36,  Hartwall  & 
Herdberg,  Berzel.  Jahresb.  4,  155.  37,  Hunt,  Amer.  Journ.  Sc.  1855,  19,  428  ;  Rep. 
Geol.  Can.  1853,  1863,  483.  38,  Th.  Wolf,  Zeitschr.  d.  Geol.  Ges.  1868,  20,  30.  39, 
G.  v.  Rath,  Pogg.  Ann.  1853,  90,  93,  297.  40,  Rammelsberg,  Ak.  Berl.  1885,  605. 
41,  Hermann,  Journ.  f.  prakt.  Chem.  1851,  54,  410.  42,  Beeke,  Tscherm.  Mitt.  1877, 
267.  43,  Bergemann,  Pogg.  Ann.  1827,  g,  267.  44,  Giwartowsky,  Bull.  soc.  nat. 
Moscow  21,  548  ;  Erdm.  Journ.  f.  prakt.  Chem.  1849,  47,  380.  45,  Fuchs,  Leonh. 
Min.  Taschb.  1823,  17,  104.  46,  Wolff,  Inaug.-Diss.,  Berl.  1843.  47,  Wolff,  ibid. 
48,  Berg,  Ofv.  Ak.  Stockh.  1844,  94.  49,  Thomson,  Min.  I,  273.  50,  Leeds,  Amer. 
Journ.  Sc.  1873,  6,  26.  51,  Hunt,  Amer.  Journ.  Sc.  1855,  19,  368.  52,  Wurtz,  Amer. 
Journ.  Sc.  1853,  10,  325.  53,  G.  v.  Rath,  Pogg.  Ann.  1853,  go,  96  ;  92,  300,  303,  290. 
54,  G.  v.  Rath,  Pogg.  Ann.  1853,  go,  93,  297.  55,  Hermann,  Journ.  f.  prakt.  Chem 
54,  410.  56,  Fuchs,  Naturg.  Min.  Kempt.  1824,  225.  57,  Lemberg,  Zeitschr.  d.  geol. 
Ges.  1887,  39,  571.  58,  G.  v.  Rath,  Pogg.  Ann.  1853,  go,  93,  297.  59,  G.  v.  Rath, 
Pogg.  Ann.  1853,  go,  99.  60,  Kiepenheuer  per  G.  v.  Rath,  Niederrh.  Ges.,  Bonn 
1879,  381.  61  Salomon  Tscherm.  Mitt.  N.  F.  15,  159.  62  Wittstein  quoted  by 
Giimbel,  Geogn.  Beschr.  Bay.  1868  2,  358.  63,  Genth,  Amer.  Journ.  Sc.  1890,  40, 
116.  64,  Rammelsberg,  Ak.  Berl.  1885,  599.  65,  Rammelsberg,  Mineralch,  1886, 
214.  66,  Rammelsberg,  Ak.  Berl.  1885,  599  ;  Zeitschr.  d.  Geol.  Ges.  1884,  36,  229. 
67,  Grandeau,  Ann.  chim.  phys.  1863,  67,  174.  68,  Gmelin,  Schweigg.  Journ.  1819, 
25,  36;  1822,  35,  348.  69,  Muir  quoted  by  Thomson,  Min.  1836,  383.  70,  Gmelin, 
Schweigg.  Journ.  1819,  25,  36  ;  1822,  35,  348. 

Orthochlorites. 

1,  F.  Heddle,  Transact.  Roy.  Soc.  Edinb.  29  ;  Groths  Zeitschr.  5,  631.  2,  Heddle. 
Groths  Zeitschr.  5,  634.  3,  Kobell,  Gel,  Anz.,  Miinchen  1854,  Ap.  10.  4,  Bruhl,  Pogg. 
Ann.  1839,  48,  185.  5,  Genth,  Amer.  Journ.  Sc.  1862,  33,  200.  6,  Adams,  Amer. 
Journ.  Sc.  1870,  49,  272  ;  Shepard,  ibid.  50,  96.  7,  Heddle,  Transact.  Roy.  Soc. 
Edinb.  29 ;  Groths  Zeitschr.  5,  631.  8,  Hartwall,  Berzel.  Jahresber.  23,  266.  9, 
Schlaepfer,  N.  Jahrb.  1891,  I,  8.  10,  Hermann,  Journ.  f.  prakt.  Chem.  1851,  53,  22. 
11,  Hunt,  Rep.  Geol.  Can.  1863,  491.  12,  Smith  &  Brush,  Amer.  Journ.  Sc.  1853, 
16,  47.  13,  Smith  &  Brush,  ibid.  14,  Rumpf,  Tscherm.  Mitt.  1873,  33.  15,  Ludwig, 
Tscherm.  Mitt.  N.  F.  12,  Heft,  1.  16,  Telek  quoted  by  Wartha,  Groths  Zeitschr.  13, 
72.  17,  Schlaepfer,  N.  Jahrb.  1891,  i,  8.  18,  v.  Fellenberg,  N.  Jahrb.  1868,  746. 
19,  v.  Hamm,  Tscherm.  Mitt.  1872,  260.  20,  Marignac,  Bibl.  univ.  Gen.  1844,  131. 
21,  Marignac,  ibid.  22,  ibid.  23,  Wartha,  Journ.  f.  prakt.  Chem.  1866,  99,  84.  24, 
Hamberg,  Geol.  For.,  Forh.  1890,  12,  580.  25,  Liebe,  N.  Jahrb.  1870,  6,  10.  26, 
F.  Heddle,  Transact.  Roy.  Soc.  Edinb.  29  ;  Groths  Zeitschr.  5,  631.  27,  Hunt,  Rep. 
Geol.  Can.  1863,  491,  469.  28,  Chatard  quoted  by  Genth,  Amer.  Phil.  Soc.  1873,  13, 
414.  29,  Clarke  &  Schneider,  Groths  Zeitschr.  18,  412.  30,  Marignac,  Ann.  de  chim. 
et  phys.  1845,  14,  60.  31,  F.  Heddle,  Transact.  Roy.  Soc.  Edinb.  29  ;  Groths  Zeitschr. 
5,  631.  32,  MacDonnell,  Proc.  Acad.  Dublin  5,  307.  33,  Merz,  Kenngotts  tfbers. 
min.  Forsch.  1858,  63.  34,  Marignac,  Ann.  de  chim.  et  phys.  1845,  14,  60.  35,  F. 
Heddle,  Trans.  Roy.  Soc.  Edinb.  29  ;  Groths  Zeitschr.  5,  631.  36,  Marignac,  Ann. 
de  chim.  et  phys.  1845,  14,  60.  37,  Hunt,  Rep.  Geol.  Can.  1863,  491.  38,  Liebe,  N. 
Jahrb.  1870,  5.  39,  Schweizer,  Pogg.  Ann.  1840,  50,  526.  40,  Schweizer.  ibid.  41, 
Pisani,  Compt.  rend.  1876,  83,  116.  42,  F.  Heddle,  Transact.  Roy.  Soc.  Edinb.  1879, 


440  REFERENCES  TO   ANALYSES 

29,  89  ;  Groths  Zeitschr.  5,  633.  43,  Delesse,  Ann.  mines  1851,  20,  155.  44,  Loretz, 
Jahrb.  d.  preufi.  d.  geol.  Landesanstalt  fiir  1884,  Berl.  1885,  133.  45,  Loretz,  Geogn. 
Beschr.  d.  Fichtelgebirges  1879,  210,  233.  46,  Pufahl  quoted  by  WeiB,  Zeitschr.  d. 
Geol.  Ges.  1879,  31,  801.  47,  Boricky,  Sitzber.  Akqad.,  Wien  1869,  59,  599.  48, 
Leeds,  Amer.  Journ.  Sc.  1873,  6,  25.  49,  Marignac,  Bibl.  univ.  Geneve  1844,  136. 
50,  Marignac,  Ann.  de  chim.  et  phys.  1844,  10,  430.  51,  L.  Smith,  Amer.  Journ.  Sc. 
1851,  n,  65.  52,  Marignac,  Ann.  de  chim.  et  phys.  1845,  14,  56.  53,  Szilasi  quoted  by 
Wartha,  Groths  Zeitschr.  13,  72.  54,  Jannasch,  N.  Jahrb.  1885,  i,  94.  55,  Jannasch, 
ibid.  56,  Wartha,  Groths  Zeitschr.  13,  72.  57,  List,  Zeitschr.  d.  Geol.  Ges.  1852,  4, 
634.  58,  Genth,  Amer.  Phil.  Soc.  1873,  13,  414.  59,  Sipocz  per  Tschermak,  Tscherm. 
Mitt.  N.  F.  12,  Heft  1.  60,  Clarke,  Amer.  Journ.  Sc.  1884,  28,  20.  61,  Varrentrapp, 
Pogg.  Ann.  1839,  48,  189.  62,  Tschermak,  Akad.  Wien  1866,  53,  521.  63,  Heddle, 
Transact.  Roy.  Soc.  Edinb.  29  ;  Groths  Zeitschr.  5,  631.  64,  Gosch  per  Cooke,  Mem. 
Amer.  Acad.  Sc.,  Boston  1874,  35  ;  1875,  453.  65,  Schrauf,  Groths  Zeitschr.  6,  345, 
383.  66,  Wilk,  Ofvers  Finska  Vetensk-Soc.  Forhandl.  1868-9,  u,  28  ;  N.  Jahrb. 

1869,  357  ;    Groths  Zeitschr.  2,  495.     67,  Schrauf,  Groths  Zeitschr.  6,  345,  383.     68, 
Rammelsberg,  Pogg.  Ann.  1856,  97,  300.     69,  v.  Drasche,  Tscherm.  Mitt.  1873,  126. 
70,  Heddle,  Groths  Zeitschr.  5,  634.     71,  Genth,  Proc.  Acad.  Sc.  Philad.  1852,  121. 
72,  Dieffenbach,  N.  Jahrb.  1855,  534.     73,  K.  v.  Hauer,  Sitzber,  Akad.  Wien,  1855, 
16,  170.     74,  F.  Heddle,  Transact.  Roy.   Soc.  Edinb.  29  ;    Groths  Zeitschr.  5,  631. 
75,  Melville  quoted  by  Lindgren.  Proc.  Calif.  Akad.  Sc.,  20.  Dec.  1887.     76,  Kobell, 
Journ.  f.  prakt.  Chem.  1839,  16,  470.     77,  Pearse,  Amer.  Journ.  Sc.  1864,  37,  222. 
78,  Pearse,  ibid.     79,  Breidenbaugh,  Amer.  Journ.  Sc.  1873,  6,  208.     80,  Rammels- 
berg, Mineralchem.  1875,  493.     81,  Field,  Phil.  Mag.  1878,  5,  52.     82,  Schrauf,  Groths 
Zeitschr.  6,  351.     83,  Garrett,  Amer.  Journ.  Sc.  1853,  15,  332.     84,  Paltauf,  Tscherm. 
Mitt.  N.  F.  12,  Heft  1.     85,  Heddle,  Groths  Zeitschr.  5,  634  ;    Hawes,  Amer.  Journ. 
Sc.  1875,  9,  451.     86,  Hawes,  ibid.     87,  Liebe,  N.  Jahrb.  1870,  8.     88,  Liebe,  N.  Jahrb. 

1870,  6,  10.     89,  Liebe,  ibid.     90,  Liebe,  N.  Jahrb.  1870,  10.     91,  Piccard,  Kenngotts 
tubers,  min.  Forsch.  1863,  203.     92,  F.  Heddle,  Transact.  Roy.  Soc.  Edinb.  29  ;  Groths 
Zeitschr.  5,  631.     93,  v.  Fellenberg,  N.  Jahrb.  1868,  746.     94,  Liebe,  N.  Jahrb.  1870,  5. 
95,  Rosam  per  Serba,  Bohm.  Ges.  Wiss.,  15  Jan.  1886.     96,  Konig  quoted  by  Genth, 
Amer.  Phil.  Soc.,  19  Sept.  1873,  13,  413.     97,  Konig  quoted  by  Genth,  ibid.     98,  Woits- 
chach,  Inaug.-Diss.,  Breslau  1881,  38.     99,  Genth,  Amer.  Phil.  Soc.  13,  417.     100, 
Genth,  ibid.     101,  P.  Keyser  quoted  by  Genth,  Amer.  Journ.  Sc.  1853,  16,  167.     102, 
P.  Keyser,  Amer.  Journ.  Sc.  1854,  18,  411.     103,  L.  Smith,  Amer.  Journ.  Sc.  1854, 
18,  376.     104,  L.   Smith,  ibid.     105,  Ludwig  quoted  by  Tschermak,  Tscherm.  Mitt. 
N.  F.  12,  Heft  1.     106,  L.  Smith,  Amer.  Journ.  Sc.  1854,  18,  376.     107,  Gintl  quoted  by 
v.  Zepharovich,  Groths  Zeitschr.  i,   372.     108,  Steinmann,   Schweigg.  Journ.   1821, 
32,  69.     109,  Steinmann,  Schweigg.  Journ.  1831,  62,  196.     110,  Klement,  Bull.  Mus. 
Roy.  d'hist.  nat.  de  Belg.  1888,  5,  162.     Ill,  R.  v.  Zeynek,  Sitzber.  Akad.  Wien,  19 
Febr.  1891, 100,  38  ;  Tscherm.  Mitt.  N.  F.  12,  Heft  1.     112,  v.  Gumbel,  Geogn.  Beschr. 
Bay.  1868,  2,  388.     113,  Janowsky,  Journ.  f.  prakt.  Chem.  1875,  JJ,  378.     114,  Clarke 
&  Schneider,  Amer.  Journ.  Sc.  1890,  40,  406  ;    Groths  Zeitschr.  18,  401.     115,  Genth, 
Amer.  Journ.  Sc.   1859,  28,  250.     116,  F.  Heddle,  Transact.  Roy.  Soc.  Edinb.  29; 
Groths  Zeitschr.   5,   631.      117,   F.  Heddle,  ibid.      118,  Obermayer  per  Tschermak, 
Tscherm.  Mitt.  N.  F.  12,  Heft  1.     119,  Pisani,  Amer.  Journ.  Sc.  1866,  41,  394.     120, 
Chatard  per   Genth,   Amer.    Phil.   Soc.    1873,   13,   414.     121,   Websky,   Zeitschr.    d. 
Geol.  Ges.  1873,  25,  391.     122,  Loretz,  Geogn.  Beschr.  d.  Fichtelgebirges  1879,  210, 
233.     123,  Delesse,  Ann.  min.  1847,  12,  221.     124,  Traube,  Min.  Schles.  1888,  249. 
125,  v.  Gumbel,  Geogn.  Beschr.  Bay.  1868,  2,  395.     126,  Delesse,  Ann.  min.  1849,  16, 
520.     127,  Loretz,  Geogn.  Beschr.  d.  Fichtelgebirges   1879,  210,  233.     128,  Loretz, 
ibid.     129,  K.  v.  Hauer,  Jahrb.  Geol.  Reichsanst.  16,  505.     130,  Sandberger,  N.  Jahrb. 
1850,  341.     131,  Rammelsberg  quoted  by  Websky,  Zeitschr.  d.  Geol.  Ges.   1879,  31, 
212.     132,  C.  Schmidt,  Groths  Zeitschr.  n,  600.     133,  Erlenmeyer,  Kopp  &  Wills 
Jahresber.  1860,  773.     134,  Erlenmeyer,  ibid.     135,  Chatard  quoted  by  Genth,  Amer. 
Phil.  Soc.,  19  Sept.  1873,  13,  413.     136,  Chatard  quoted  by  Genth,  ibid.     137,  Zeynek 
quoted  by  Tschermak,  Tscherm.  Mitt.  N.  F.  12,  Heft  1.     138,  K.  v.  Hauer,  Jahrb. 
Geol.  Reichsanst.  5,  337.     139,  Suylsteke  quoted  by  Tschermak,  Tscherm.  Mitt.  N.  F. 
12,  Heft  1.     140,  Klement,  Tscherm.  Mitt.  N.  F.  i,  365.     141,  Damour,  Ann.  de 
chim.  et  phys.  1860,  58,  99.     142,  Klement,  Tscherm.  Mitt.  N.  F.  12,  Heft  1.     143, 
Genth,  Amer.  Phil.  Soc.  1873,  414.     144,  Chatard  quoted  by  Genth,  ibid.     145,  Chatard 
quoted  by  Genth,  ibid.     146,  F.  Heddle,  Transact.  Roy.  Soc.  Edinb.  29  ;  Groths  Zeitschr. 
5,  631.     147,  Jacobs  quoted  by  Dathe,  Zeitschr.  d.  Geol.   Ges.   1887,  39,  505.     148* 
Rammelsberg,  Mineralchem.  1860,  538.     149,  F.  Heddle,  Transact.  Roy.  Soc.  Edinb. 


REFERENCES   TO   ANALYSES  441 

29  ;  Groths  Zeitschr.  5,  631.  150,  Kobell,  Journ.  f.  prakt.  Chem.  16,  470.  151, 
Kobell,  ibid.  152,  Fellenberg,  N.  Jahrb.  1868,  746.  153,  F.  Heddle,  Transact.  Roy. 
Soc.  Edinb.  29;  Groths  Zeitschr.  5,  631.  154,  Egger,  Tscherm.  Mitt.  1874,  244.  155, 
Bock,  Inaug.-Diss.,  Breslau  1868,  4.  156  Igelstrom,  Journ.  f.  prakt.  Chem.  1861,  84, 
480.  157,  F.  Heddle,  Transact.  Hoy.  Soc.  Edinb.  29  ;  Groths  Zeitschr.  5,  631.  158, 
Heddle,  ibid.  159,  Santerson  quoted  by  Eichstadt,  Geol.  For.  Forh.  7,  333  ;  Groths 
Zeitschr.  10,  511.  160,  Heddle,  Groths  Zeitschr.  5,  634.  161,  Damour,  Ann.  min. 
1857,  Jj,  284.  162,  Craw,  Amer.  Journ.  Sc.  1852,  13,  222.  163,  Craw,  ibid.  164, 
van  Riesen  quoted  by  Cohen,  Naturw.  Ver.  Neuvorp.  &  Riigen,  1886,  77.  165-6,  Erd- 
mann,  Ann.  min.  1853,  3,  729.  167,  Marignac,  Ann.  de  chim.  et  phys.  1845,  14,  56. 
168,  F.  Heddle,  Transact.  Roy.  Soc.  Edinb.  29  ;  Groths  Zeitschr.  5,  631.  169,  Ort- 
mann,  Tscherm.  Mitt.  N.  F.  12,  Heft  1.  170,  Schlaepfer,  N.  Jahrb.  1891,  j,  8.  171, 
Neminar,  Tscherm.  Mitt.  1874,  177.  172,  Clarke  &  Schneider,  Groths  Zeitschr.  18, 
401.  173,  Hermann,  Journ.  f.  prakt.  Chem.  1851,  53,  22.  174,  Herzog  N.  v.  Leuchten- 
berg,  Russ.  min.  Ges.  1866,  i,  33  ;  Bull.  acad.  St.  Petersb.  g,  188.  175,  Herzog  N.  v. 
Leuchtenberg,  ibid.  176,  Lagorio,  Tscherm.  Mitt.  N.  F.  8,  497.  177,  Brun,  Groths 
Zeitschr.  7,  390.  178,  Hermann,  Journ.  f.  prakt.  Chem.  1847,  40,  15.  179,  Pearse, 
Amer.  Journ.  Sc.  1864,  37,  222.  180,  Hardmann,  Proc.  Roy.  Ir.  Acad.  1878,  j,  161. 
181,  Wurtz,  Sillim.  Amer.  Journ.  1850,  10,  80;  Dana,  Min.  1850,  679.  182,  Igel- 
strom, Ofo,  Acad.  Stockholm  1868,  29  ;  Journ.  f.  prakt.  Chem.  104,  463.  183,  Loretz, 
Jahrb.  d.  preuB.  geol.  Landesanstalt  fur  1884,  Berl.  1885,  133.  184,  F.  Heddle.  Transact. 
Roy.  Soc.  Edinb.  29  ;  Groths  Zeitschr.  5,  631.  185,  Heddle,  Groths  Zeitschr.  5,  634. 
186,  Heddle,  ibid.  187,  Gintl  per  v.  Zepparovich,  Tscherm.  Mitt.  1874,  7.  188, 
van  Weryecke  quoted  by  Groth,  Groths  Zeitschr.  J,  510.  189,  Kommonen,  Russ.  min. 
Ges.  1842,  64;  Pogg.  Ann.  1843,  59,  492.  190,  Kommonen,  ibid.  191,  Hermann, 
Journ.  f.  prakt.  Chem.  1847,  40,  13.  192,  Clarke  &  Schneider,  Groths  Zeitschr.  18, 
401.  193,  Herzog  N.  v.  Leuchtenberg,  Russ.  min.  Ges.  1868,  3,  293  ;  per  Koks- 
charow,  Mat.  Min.  Rufil.  5,  369.  194,  Herzog  N.  v.  Leuchtenberg,  ibid.  195  N.  v. 
Zinin,  Russ.  min.  Ges.  1868,  3,  293 ;  per  Kokscharow,  Mat.  Min.  Rufil.  5,  369. 
196,  N.  v.  Zinin,  ibid.  197,  Hermann,  Journ.  f.  prakt.  Chem.  1851,  53,  21.  198, 
Burton  quoted  by  Dana,  Min.  1868,  499.  199,  Hammerschlag  quoted  by  Tschermak, 
Tscherm.  Mitt.  N.  F.  12,  Heft  1.  200,  F.  Heddle,  Transact.  Roy.  Soc.  Edinb.  29  ; 
Groths  Zeitschr.  5,  631.  201,  Delesse,  Ann.  de  chim.  et  phys.  1843,  9,  396.  202, 
Struve  quoted  by  Kokscharow,  Mat.  Min.  Rufil.  3,  236.  203,  Struve  quoted  by  Koks- 
charow, ibid.  204,  Janowsky,  Ber.  d.  D.  chem.  Ges.  1873,  1230.  205,  Kobell,  Journ. 
f.  prakt.  Chem.  1839,  16,  470.  208,  Varrentrapp,  Pogg.  Ann.  1839,  48,  189.  207, 
Flight  quoted  by  Maskelyne,  Journ.  Chem.  Soc.  1871,  9,  9.  208,  Penfield  &  Sperry, 
Amer.  Journ.  Sc.  1886,  32,  307.  209,  Firtsch,  Sitzber.  Akad.  Wien  1890,  99,  417. 
210,  F.  Nies,  N.  Jahrb.  1873,  321.  211,  Smith,  Amer.  Journ.  Sc.  1854,  18,  376.  212, 
Rammelsberg,  Mineralchem.  1860,  851.  213,  L.  Smith,  Amer.  Journ.  Sc.  1866,  42, 
91.  214,  Flight  quoted  by  Maskelyne,  Journ.  Chem.  Soc.  1871,  9,  9. 

Tourmalines. 

The  numbers  following  the  analysts'  names  are  the  numbers  of  their  tests  as 

described  in  the  following  papers  : 

Rammelsberg,  Pogg.  Ann.  1870,  139,  379,  547  ;  Mineralchem.  1875,  541.  Riggs, 
Amer.  Journ.  Sc.  1888,  35,  40.  Jannasch  &  Calb,  Ber.  d.  D.  chem.  Ges.  1889,  22, 
219.  1,  Rammelsberg  14.  2,  Riggs  18.  3,  Rammelsberg  31.  4,  Rammelsberg  20. 

5,  Rammelsberg   13.     6,   Scharizer,   Groths   Zeitschr.    15,   344.     7,   Jannasch   7.     8, 
Riggs  2.     9,  Riggs  14.     10,  Riggs  15.     11,  Cossa,  Groths  Zeitschr.  7,  14.     12,  Jannasch 

6.  13,  Riggs  3.     14,  Riggs  19.     15,  Rammelsberg  21.     16,  Riggs  16.     17,  Scharizer, 
Groths  Zeitschr.  75,  344.      18,  Sommerland  quoted  by  v.  Groddeck,  Zeitschr.  d.  GeoL 
Ges.  1884,  36,  642.     19,  Rammelsberg  6.     20,  Rammelsberg  28.     21,  Riggs  17.     22, 
Riggs   13.     23,  Jannasch  3.     24,  Rammelsberg  18.     25,  Jannasch  4.     26,  Riggs  5. 
27,  Rammelsberg  22.     28,  Sauer,  Zeitschr.  d.  Geol.  Ges.  38,  704.     29,  Rammelsberg  25. 
30,  Rammelsberg  11.     31,  Jannasch  9.     32,  Rammelsberg  26.     33,  Rammelsberg  2. 
34,  Rammelsberg  17.     35,  Rammelsberg  23.     36,  Riggs  7.     37,  Riggs  9.     38,  Riggs  8. 
39,  Rammelsberg  5.     40,  Engelmann,  Inaug.-Diss.,  Bern  1877.     41,  Rammelsberg  27. 
42,  Rammelsberg  19.     43,  Rammelsberg  12.     44,  Jannasch  5.     45,  Gill,  Johns  Hopkins 
Univ.  Circ.  No.  75.     46,  Schwartz  quoted  by  v.  Groddeck,  Zeitschr.  d.  Geol.  Ges.  1887, 
39,  238.     47,  Rammelsberg  3.     48,  Rammelsberg  4.     49,  Rammelsberg  1.     50,  Ram- 
melsberg 15.     51,  Rammelsberg  7.     52,  Rammelsberg  22.     53,  Riggs  4.     54,  Scharizer, 
Groths  Zeitschr.  75,  344.     55,  Rammelsberg  24.     56,  Rammelsberg  9.     57,  Rammels- 


442  REFERENCES   TO   ANALYSES 

berg  10.  58,  Rammelsberg  29.  59,  Riggs  10.  60,  Rammelsberg  8.  61,  Rammelsberg 
33.  62,  Jannasch  1.  63,  Riggs  12.  64,  Riggs  11.  65,  Rammelsberg  16.  66,  Jan- 
nasch  2.  67,  Riggs  20.  68,  Rammelsberg  32.  69,  Riggs  6. 

Felspars. 

1,  F.  Heddle,  Trans.  Roy.  Soc.  Edinb.  1877,  28,  197  ;  Min.  Soc.  Lond.  1881,  4, 
197.  2,  Raimondi,  Min.  Perou  1878,  309.  3,  Deville,  Ann.  de  chim.  et  phys.  1854, 
40,  283.  4,  Delesse,  Ann.  de  chim.  et  phys.  1848,  24.  5,  F.  Heddle,  Trans.  Roy.  Soc. 
Edinb.  1877,  28,  197  ;  Min.  Soc.  Lond.  1881,  4,  197  ;  Groths  Zeitschr.  2,  651  ;  7,  190. 
6,  G.  v.  Rath,  Niederrh.  Ges.,  Bonn  1869,  108  ;  Pogg.  Ann.  1869,  138,  464  ;  1871, 
Erg.-Bd.  5,  431.  7,  Kersten,  Journ.  f.  prakt.  Chem.  1846,  37,  174.  8,  Kersten,  N. 
Jahrb.  1845,  653.  9,  Des  Cloizeaux,  Bull.  soc.  min.  Paris  1884,  7,  255.  10,  Erdmann. 
Min.  1853,  326.  11,  Bothe  quoted  by  G.  v.  Rath,  Trach.  Siebengeb.,  Bonn  1861,  14. 
12,  Laurent,  Ann.  de  chim.  et  phys.  59,  108.  13,  J.  L.  Smith  per  Genth,  Min. 
N.  C.  1891,  55.  14,  K6nig,  Zeitschr.  d.  Geol.  Ges.  1868,  20,  374.  15,  F.  Heddle,  Trans. 
Roy.  Soc.  Edinb.  1877,  28,  197  ;  Min.  Soc.  London  1881,  4,  197  ;  Groths  Zeitschr.  2, 
651  ;  7,  190.  16,  Schnorf  quoted  by  v.  Fritsch,  Kenngott,  Ubers.  min.  Forsch.  1862-5, 
191.  17,  Merian,  N.  Jahrb.  1885,  Beil.-Bd.  3,  296.  18,  Kemp,  Ann.  Journ.  So.  1888, 
36,  247.  19,  Struve,  Kenngott,  tJbers.  min.  Forsch.  1862-5,  190.  20,  Struve,  Ram- 
melsberg, Mineralchem.  1875,  569.  21,  Duparc  per  Fouque,  Bull.  soc.  Paris 
1894,  17,  360.  22,  BrSgger  &  Reusch,  Zeitschr.  d.  Geol.  Ges.  1875,  27,  676.  23, 
Fellner,  Verh.  d.  Geol.  Reichsanst.  1867,  770,  286.  24,  G.  v.  Rath,  Zeitschr.  d. 
Geol.  Ges.  1895,  27,  328;  Pogg.  Ann.  1875,  155,  65;  N.  Jahrb.  1875,  397.  25, 
G.  v.  Rath,  Nat.-hist.  Ver.  Bonn  1875,  Korr.-Bl.  95.  26,  Petersen,  Groths 
Zeitschr.  9,  394.  27,  Haughton,  Qu.  Journ.  geol.  Soc.  1862,  18,  403 ;  Rep.  Brit. 
Assoc.  1863,  55.  28,  Jackson,  Amer.  Journ.  Sc.  1866,  42,  107.  29,  Hunt,  Amer. 
Journ.  Sc.  1864,  38,  97,  180.  30,  F.  Heddle,  Trans.  Roy.  Soc.  Edinb.  1877, 
28,  197  ;  Min.  Soc.  Lond.  1881,  4,  197 ;  Groths  Zeitschr.  '2,  651  ;  7,  190.  31, 
Jackson,  Amer.  Journ.  Sc.  1866,  42,  107.  32,  Streng,  N.  Jahrb.  1867,  537.  33, 
Des  Cloizeaux,  Bull.  soc.  min.  Paris  1884,  7,  255.  34,  Resales,  Pogg.  Ann.  1842, 
55,  109.  35,  Konig,  Zeitschr.  d.  Geol.  Ges.  1868,  20,  372.  36,  Haughton,  Phil. 
Mag.  1870,  40,  59.  37,  Pisani,  Bull.  soc.  Paris  1885,  8,  6.  38,  Siemiradzki,  N.  Jahrb. 
1886,  Beil.-Bd.  4,  209.  39,  Fellner,  Verh.  d.  Geol.  Reichsanst.  1867,  770,  286.  40, 
Scheerer,  Pogg.  Ann.  1845,  64,  153.  41,  G.  v.  Rath,  Pogg.  Ann.  1872,  147,  277.  42, 
G.  v.  Rath,  Niederrh.  Ges.,  Bonn  1875,  60  ;  Zeitschr.  d.  Geol.  Ges.  1875,  27,  331  ; 
N.  Jahrb.  1875,  397,  Pogg.  Ann.  755,  65.  43,  Des  Cloizeaux,  Bull.  soc.  min.  Paris 
1884,  7,  277.  44,  Berzelius,  Arsber.  1824,  4,  147  ;  1839,  ig,  302.  45,  G.  v.  Rath, 
Berl.  Akad.  1876,  164  ;  N.  Jahrb.  1876,  706.  46,  Haughton,  Phil.  Mag.  1870,  40,  59. 
47,  Hunt,  Amer.  Journ.  Sc.  1864,  38,  97,  180.  48,  Fouque,  N.  Jahrb.  1876,  66.  49, 
F.  Heddle,  Trans.  Roy.  Soc.  Edinb.  1877,  28,  197 ;  Min.  Soc.  Lond.  1881,  4,  197  ;  Groths 
Zeitschr.  2,  651  ;  7,  190.  50,  Delesse,  Ann.  de  chim.  et  phys.  1850,  30,  81  ;  Bull, 
soc.  geol.  7,  528.  51,  Delesse,  N.  Jahrb.  1851,  169.  52,  F.  Heddle,  Trans.  Roy.  Soc. 
Edinb.  1877,  28,  197  ;  Min.  Soc.  Lond.  1881,  4,  197  ;  Groths  Zeitschr.  2,  651  ;  7,  190. 
53,  v.  Giimbel,  Beschr.  Bay.  1868,  2,  344.  54,  G.  v.  Rath,  Pogg.  Ann.  1871,  144,  256. 
55,  Delesse,  Ann.  mines  1849,  16,  362  ;  1851,  ig,  149.  56,  Penfield  &  Sperry,  Amer. 
Journ.  Sc.  1887,  34,  390.  57,  G.  Rose,  Reise  1837,  J,  144  ;  1842,  2,  511  ;  Pogg.  Ann. 
1841,  52,  470.  58,  F.  Heddle,  Trans.  Roy.  Soc.  Edinb.  1877,  28,  197.  59,  Compt. 
rend.  1844,  19,  46.  60,  Delesse,  ibid.  61,  Wollemann,  Groths  Zeitschr.  14,  625.  62, 
Hebenstreit,  Groths  Zeitschr.  2,  103.  63,  Seneca,  Beschr.  Bad.  1861,  62.  64,  Fouque, 
Compt.  rend.  19,  46.  65,  Pisani,  Bull.  soc.  Paris  1894,  17,  369.  66,  G.  v.  Rath,  Pogg. 
Ann.  1871,  144,  20.  67,  G.  v.  Rath,  Pogg.  Ann.  1871,  144,  235  ;  Niederrhein.  Ges., 
Bonn  1871,  16,  78.  68,  Lemberg,  Zeitschr.  d.  Geol.  Ges.  1887,  39,  569.  69,  G.  v. 
Rath,  Pogg.  Ann.  1872.  147,  275.  70,  F.  Heddle,  Trans.  Roy.  Soc.  Edinb.  1877,  28, 
197  ;  Min.  Soc.  Lond.  1881,  4,  197  ;  Groths  Zeitschr.  2f  651  :  7,  190.  71,  Delesse, 
Compt.  rend.  1844,  ig,  46  :  Zeitschr.  d.  Geol.  Ges.  1853,  5,  687.  72,  Hagen,  Pogg. 
Ann.  1838,  44,  329.  73,  Kerndt,  Journ.  f.  prakt.  Chem.  1848,  43,  214.  74,  Smith  & 
Brush,  Amer.  Journ.  1853,  15,  211  ;  16,  44.  75,  Pisani,  Bull.  soc.  Paris  1885,  <§,  6. 
76,  Kersten,  N.  Jahrb.  1845,  653.  77,  Rocholl  quoted  by  Rammelsberg,  Mineralchem. 
1875,  575.  78,  Streng,  N.  Jahrb.  1867,  537.  79,  Fouque,  Bull.  soc.  min.  Paris,  1894 
J7,  363.  80,  Bonsdorff,  Moberg  per  Rammelsberg,  Mineralchem.  1875,  574. 
81,  Deville,  Bull.  soc.  geol.  1848-9,  6,  410.  82,  K.  v.  Hauer,  Verh.  d.  Geol.  Reichsanst. 
1867,  58,  14,  144;  1869,  12,  51;  1867,  146,  12,  13,  118,  60,  354,  119.  83,  Delesse, 
Ann.  min.  1847,  12,  258.  84,  Domeyko,  Min.  1879,  562-5.  85,  Thomson,  Phil.  Mag. 


REFERENCES   TO   ANALYSES  443 

1843,  22,  190.  86,  Delesse,  Ann.  min.  1847,  12,  256.  87,  Sartorius  v.  Waltershausen, 
Vulk.  Gest.  1853,  34.  88,  Segeth,  Bull.  sc.  Petersburg  1040,  7,  25  ;  Journ.  f.  prakt. 
Chem.  1840,  20,  253.  89,  Siemiradzki,  N.  Jahrb.  1886,  Beil.-Bd.  4,  223.  90,  B.  Koto, 
Groths  Zeitschr.  13,  179.  91,  K.  v.  Hauer,  Verb.  d.  Geol.  Reichsanst.  1867,  58,  14.  144  ; 
1869,  12,  51  ;  1867,  146,  12,  13,  118,  60,  354,  119.  92,  Mattirolo  quoted  by  Cossa, 
Groths  Zeitschr.  7,  629.  93,  Behr  quoted  by  Benecke-Cohen,  Umgeg.  Heidelberg  1881, 
139.  94,  Delesse,  Ann.  min.  1849,  16,  513.  95,  Hunt,  Erdm.  Journ.  1855,  66,  149  ; 
Geol.  Surv.  Can.  1857,  357  :  1863,  478.  96,  G.  v.  Rath,  Pogg,  Ann.  1871, 
144,  247.  97,  Swiatkowsky  quoted  by  Benecke-Cohen,  Umgeg.  Heidelberg  1881, 
139.  98,  Tschermak,  Akad.  Wien  1864,  50,  586.  99,  Klement,  Tscherm.  Mitt. 
N.  F.  i,  366.  100,  Lehunt,  Ed.  N.  Phil.  Journ.  1832,  86.  101,  Zittel,  N.  Jahrb. 
1866,  641.  102,  Doelter,  Tscherm.  Mitt.  1874,  15;  1873,  62.  103.  Delter,  ibid. 
104,  Doelter,  ibid.  105,  G.  v.  Rath,  N.  Jahrb.  1875,  397,  jPogg.  Ann.  155,  65  ; 
Zeitschr.  d.  Geol.  Ges.  27,  332.  106,  Doelter,  Tscherm.  Mitt.  1873,  62  ;  1874, 
15.  107,  Doelter,  ibid.  108,  G.  v.  Rath,  Niederrh.  Ges.,  Bonn  1873,  231  ;  Monatsber. 
d.  Berl.  Akad.  1874,  26  ;  Pogg.  Ann.  1874,  152,  39  ;  1875,  155,  64  ;  Zeitschr.  d.  Geol. 
Ges.  1875,  27,  302-24.  109,  G.  v.  Rath,  Pogg.  Ann.  1873,  Erg.-Bd.  6,  380.  110, 
E.  E.  Schmid,  Pogg.  Ann.  1863,  ng,  188.  Ill,  Sartorius  v.  Waltershausen,  Vulk. 
Ges.  953,  24.  112,  Abich,  Pogg.  Ann.  1840,  50,  347.  113,  Ricciardi,  Gazz.  chim. 
ital.  1881,  138.  114,  Sartorius  v.  Waltershausen,  Vulk.  Ges.  1853,  34.  115,  Hunt, 
Amer.  Journ.  Sc.  1864,  38,  177.  116,  Streng,  Zeitschr.  d.  Geol.  Ges.  1858,  10,  135, 
Berg-  u.  Hiittenm.  Ztg.  1861,  20,  265.  117,  Jannasch,  N.  Jahrb.  1884,  2,  42.  118, 
Williams,  N.  Jahrb.  1887,  Beil.-Bd.  5,  417.  119,  Dulk  per  Rammelsberg.  Mineral- 
chem.  1875,  564,  Nr.  9.  120,  K.  v.  Hauer,  Verh.  d.  Geol.  Reichsanst.  1867,  58,  14, 
144;  1869,  12,  51;  1867,  146,  12,  13,  118,  60,  354,  119.  121,  Hunt,  Erdm.  Journ. 
1855,  66,  149  ;  Geol.  Surv.  Can.  1857,  357  ;  1863,  478.  122,  Domeyko,  Min.  1879, 
562-5.  123,  Klement,  Groths  Zeitschr.  18,  529.  124,  Wilk,  Groths  Zeitschr.  7,  77. 
125,  Deville.  Bull.  soc.  geol.  1848,  1849,  6,  410.  126,  Hunt,  Erdm.  Journ.  1855,  66, 
149  ;  Geol.  Surv.  Can.  1857,  357  ;  1863,  478.  127,  Hunt,  ibid.  128,  Rammelsberg, 
Mineralchem.,  5  Suppl.,  1853,  48.  129,  Hunt,  Erdm.  Journ.  1855,  66,  149  ;  Geol. 
Surv.  Can.  1857,  357  ;  1863,  478.  130,  Bonsdorff  &  Laurell,  Vet.  Akad.  1876,  169. 
131.  G.  v.  Rath,  Pogg.  Ann.  1871,  144,  245.  132,  Lemberg,  Zeitschr.  d.  Geol.  Ges. 
1888,  40,  645.  133,  Wilk,  Groths  Zeitschr.  n,  315.  134,  Hunt,  Erdm.  Journ.  1855, 
66,  149  ;  Geol.  Surv.  Can.  1857,  357  ;  1863,  478.  135,  Payne  quoted  by  Dana,  Min. 
1892,  337,  336.  136,  G.  v.  Rath,  Niederrh.  Ges.,  Bonn  1873,  231  ;  Monatsb.  d.  Berl. 
Akad.  1874,  26  :  Pogg.  Ann.  1874,  152,  39  ;  1875,  J55,  64  ;  Zeitschr.  d.  Geol.  Ges. 
1875,  27,  302-24.  137,  Laspeyres,  Zeitschr.  d.  Geol.  Ges.  1866,  18,  193.  138,  G.  v. 
Rath,  Niederrh.  Ges.,  Bonn  1873,  231  ;  Monatsb.  d.  Berl.  Akad.  1874,  26  ;  Pogg.  Ann. 

1874,  152,  39  ;    1875,  155,  64  ;    Zeitschr.  d.  Geol.  Ges.  1875,  27,  302-24.     139,  Maly, 
Sitzb.  Ak.  Wien  1885,  gi,  65.     140,  Laurell,  Vet.  Akad.  Handl.  Stockh.   1853,   14. 
141,  Heddle,  Trans.  Roy.  Soc.  Edinb.  1877,  28,  197  ;    Groths  Zeitschr.  2,  654.     142, 
Williams,  N.  Jahrb.  1887,  Beil.-Bd.  5,  417.     143,  Tschermak,  Min.  Mitt.  1874,  269  ; 

1875,  41.     144,  Hofer,  N.  Jahrb.   1871,   128.     145,  Hofer,  ibid.     146,  Deville,  Bull. 
soc.  geol.  1848-9,  6,  410.     147,  Lemberg,  Zeitschr.  d.  Geol.  Ges.  1870,  22,  337,  342, 
361.     148,  Jewreinow,  Berg-  u.  Hiittenm.  Ztg.  1853,  7,  196.     149,  Clarke  quoted  by 
Kum,  Amer.  Journ.  Sc.  1888,  36,  222.     150,  Knop,  Kaiserst.  1892,  101.     151,  Heddle, 
Trans.  Roy.  Soc.  Edinb.   1877,  28,   197  ;    Groths  Zeitschr,  2,  654.      152,  Haushofer, 
Groths  Zeitschr.  3,  602.     153,  Haughton,  Qu.  Journ.  geol.  soc.  1862,  18,  403  ;    Rep. 
Brit.  Assoc.  1863,  55.     154,  Koch,  Tscherm.  Mitt.  1877,  330.     155,  Lory,  Bull.  soc. 
geol.   1849-50,   7,   542.     156,   Lory,  ibid.     157,  Keller  quoted  by  Genth,  Amer.  Phil. 
Soc.,  2  Oct.  1885.     158,  Streng,  N.  Jahrb.  1867,  537.     159,  Hunt,  Erdm.  Journ.  1855, 
66,  149  ;  Geol.  Surv.  Can.  1857,  357  ;  1863,  478.     160,  Wedel,  Jahrb.  d.  Geol.  Landesans 
1890.     161,  Delesse,  Ann.  min.  1853,  3,  374.     162,  Chatard  per  Genth,  Amer.   Phil. 
Soc.  1873,  13,  397  ;   Min.  N.  C.  1891,  55.     163,  Delesse,  Ann.  Min.    1848,   13,  675  ; 
1853,  3,  374.     164,  K.  v.  Hauer,  Verh.  d.  Geol.  Reichsanst.  1867,  58,  14,  144  ;    1869, 
12,  51  ;    1867,  146,  12,  13,  118,  60,  354,  119.     165,  Abich,  Pogg.  Ann.  1840,  51,  523. 
166,  Dirvell,  Bull.  soc.  min.  Paris  1884,  7,  329.     167,  Foullon  quoted  by  Schuster,  Jahrb. 
d.  Geol.  Reichsanst.,  Wien  1887,  37,  219.     168,  G.  v.  Rath,  Niederrh.  Ges.,  Bonn  1873, 
231  ;   Monatsber.  d.  Berl.  Akad.  1874,  26  ;   Pogg.  Ann.  1874,  152,  39  ;    1875,  755,  64  ; 
Zeitschr.  d.  Geol.  Ges.  1875,  27.  302-24.     169,  Chatard  quoted  by  Genth,  Amer.  Phil. 
Soc.,  19  Sept.  1873,  13,  397.     170,  Delesse,  Ann.  min.  1848,  13,  675.     171,  Hunt,  Amer. 
Journ.  Sc.  1864,  38,  180,  197.     172,  Petersen,  N.  Jahrb.  1874,  270.     173,  G.  v.  Rath, 
Zeitschr.  d.  Geol.  Ges.  1875,  27,  325  ;   Pogg.  Ann.  155,  65  ;   N.  Jahrb.  1875,  397.     174, 
Des  Cloizeaux,  Bull.  soc.  min.  Paris  1884,  7,  255.     175,  Delesse,  Ann.  min.  1848,  13, 


444  REFERENCES  TO   ANALYSES 

675.  176,  Chrustschoff,  Compt.  rend.  1891,  112,  1070.  177,  Glocker,  Fogg.  Ann. 
1844,  61,  385  ;  Journ.  f.  prakt.  Chem.  1845,  34,  494  ;  Synops  Min.  1847,  143.  178, 
Rammelsberg,  Mineralchem.,  5  Suppl.,  1853,  48.  179,  G.  v.  Rath,  Niederrh.  Ges., 
Bonn  1873,  231  ;  Monatsber.  d.  Berl.  Akad.  1874,  26  ;  Pogg.  Ann.  1874,  152,  39  ; 
1875,  J55,  64  ;  Zeitschr.  d.  Geol.  Ges.  1875,  27,  302-24.  180,  Goldschmidt,  N.  Jahrb. 
1881,  Beil.-Bd.  i,  207.  181,  Goldschmidt,  ibid.  182,  K.  v.  Hauer,  Verh.  d.  Geol. 
Reichsanst.  1867,  58,  14,  144  ;  1869,  12,  51 ;  1867,  146,  12,  13,  118,  60,  354,  119.  183, 
Franke  per  Rammelsberg,  Mineralchem.  1860,  609.  184,  Heddle,  Trans.  Roy. 
Soc.  Edinb.  1877,  28,  197  ;  Groths  Zeitschr.  2,  654.  185,  K.  v.  Hauer,  Verh.  d.  Geol. 
Reichsanst.  1867,  58,  14,  144;  1869,  12,  51;  1867,  146,  12,  13,  118,  60,  354,  119. 
186,  Jacobson  quoted  by  Rammelsberg,  Mineralchem.  1860,  606.  187,  Varrentrapp 
quoted  by  G.  Rose,  Pogg.  Ann.  52,  465. 


NAME  INDEX 


Abegg  &  Bodlander,  266,  267 

Abich,  421,  425 

Albrecht,  230,  233 

Alexander,  234 

Allen  &  Shepherd,  158,  162,  170,  175,  305, 

320 

Ammon,  v.,  367 
Apfelstadt,  206,  207,  233 
Armstrong,  259,  266,  267,  311 
Arrhenius,  229,  266,  326 
Arzruni,  282,  292 
Asch,  D.,  16,  235,  241 
Asch,  W.,  16,  97,  235,  322 
Asch,  W.,  &  Asch,  D.,  216,  235 
Ascher,  199 

Aston  ;   see  Ramsay  &  Aston 
Atterberg,  134 
Azakawa,  223 


B 

Baeyer,  Ad.  v.,  281,  311 

Baeyer  &  Villiger,  278 

Baldus,  230,  235 

Baltzer,  367 

Becke,  281,  284,  285,  307 

Becquerel,  H.,  274 

Behr,  419 

Behring,  223,  224 

Bel,  Le,  281,  314 

Bemmelen,  J.  M.  van,  70 

Benrath,  236 

Berg,  380 

Bergemann,  3,  380 

Berlin,  376 

Berthelot,  269 

Berthier,  236 

Berthollet,  293,  302-304 

Berzelius,  3,  6,  10,  48,  270,  353,  358,  413, 

415 

Biel,  232 
Biot,  312 

Birch-Hirschfetd,  234 
Bischof,  C.,  107,  113,  124,  126,  127,  128, 

129,  131,  428,  430,  431 
Black,  221,  225 
Blank,  234 
Blau,  369 

Blomstrand,  17,  19,  21,  98,  257,  321 
Blythe,  371 
Bock,  399 

Bodlander  ;   see  Abegg  &  Bodlander 
Bodecker,  4,  6 
Boke,  234 


Bois  Reymond,  326 

Bombicci,  6,  11 

Bomstein,  223 

Bonsdorff,  4,  6,  362,  419 

Bonsdorff  &  Laurell,  423 

Boricky,  373,  389 

Bothe,  413 

Bousfield,  259 

Brandhorst  &  Kraut,  102 

Braun,  J.  v.,  277 

Brauns,  6,  285,  312,  314,  315,  316 

Bravais,  285,  289,  316 

Bredig,  270 

Breidenbaugh,  393 

Breidenstein,  356 

Breunlin,  136 

Brewster,  312 

Brogger,  9 

Bromeis,  365,  373 

Brongniart  &  Malaguti,  108 

Brown,  292 

Bruck,  230,  233 

Briiel,  385 

Bruhl,  312 

Brun,  401 

Brunner,  136 

Brush,  371 

Brush  ;    see  Smith  &  Brush 

Biichner,  136,  434 

Bullouin,  M.,  283 

Burton,  403 

Buttlerow,  271 


Calb  ;    see  Jannasch  &  Calb 

Caldwell,  R.  J.,  266,  267 

Candelot,  E.,  196 

Carrara  &  Vespignani,  228 

Chatard,  367,  371,  387,  397,  399,  425 

Chatelier,  H.  Le,  110,  157,  158,  163,  164, 

196,  197 

Chatoney  &  Rivot,  156,  163,  164 
Chrustschoff,  427 

Clarke,  4,  6,  9,  23,  26,  27.  28,  65-70,  296 
Clarke  &  Schneider,  387,  395,  401,  403 
Claus,  309,  310 
Cobb,  J.  W.,  162 
Cleef,  van,  262 
Coehn,  278 
Cohen,  367 
Collie  &  Tickle,  278 
Cooke,  W.  F.,  266,  267,  371 
Cossa,  369,  371,  406 
Crawe,  365 
Croly,  de,  223 


445 


446 


NAME   INDEX 


Cronquist,  430 
Crossley,  367,  374 
Curie,  274 


D 


Dalkuhara,  7 

Dalton,  J.,  304 

Dammer,  96 

Damour,  4,  65,  66,  70,  72,  77,  358,  361, 

362,  374,  399 
Dana,  A.  G.,  354 
Darapsky,  358 
Davis  &  Fowler,  229 
Debray,  101 
Decaisne,  234 
Delesse,  361,  369,  373,  397,  403,  413,  415, 

417,  419,  421,  425,  427 
Delter,  421 

Desch,  C.  H.,  113,  159,  162,  178,  253,  319 
Detzner,  230 
Deval,  198 

Deville,  411,  419,  423 
Dewey,  371 
Diamant,  311 
Dieffenbach,  391 
Dirvell,  413,  415,  425,  427 
Dobereiner,  3 
Dollken,  226 
Doelter,  11,  47,  70,  284 
Domeyko,  419,  421 
Donnan,  229 
Donnell,  M.,  387 
Drasche,  v.,  355 
Dreschfeld,  202 
Dulk,  421 
Dumas,  236 
Du-Bois-Reymond,  326 
Dupare,  413 
Durscher,  358 

E 

Ebell ;   see  Knapp  &  Ebell 

Egger,  399 

Ehrlich,  P.,  222,  223,  224,  225,  323 

Eisner,  136,  151 

Engelmann,  408 

Erdmann,  361,  401 

Erdmenger,  157,  163,  164 

Erlenmeyer,  257,  324,  397 

Escher,  230 

Euler,  266,  267 

Eykmann,  259 


Federow,  v.,  312 

Fehling,  435 

Feichtinger,  154,  178,  183-188,  190,  434, 

435,  436 
Feiler,  230,  232 
Fellenberg,  v.,  387,  393,  399 
Fellner,  413,  415 
Feret,  158 

Fermi  &  Pernossi,  223 
Ficinus,  373 


Field,  393 

Filippi.  de  F.,  316 

Finkener,  100,  102 

Firtsch,  405 

Fischer,  E.,  224,  271,  281 

Fischer,  E.,  &  Passmore,  F.,  271 

Fischer,  F.,  237,  254,  434,  435 

Fletcher,  T.,  199,  200 

Flett,  134 

Flight,  405 

Fock,  281,  283,  284,  285,  299 

Forster,  241 

Forchhammer,  108 

Fouque,  415,  417,  419 

Fowler ;    see  Davis  &  Fowler 

Francis,  417 

Franke,  427 

Frankenheim,  285,  289,  316 

Freinkel ;    see  Kehrmann  &  Freinkel 

Fremery,  17 

Fremy,  4,  155,  193 

Fremy  ;  see  Pelouze  &  Fremy 

Freund,  231 

Friedel,  G.,  45,  72,  257 

Friedheim,  17-22,  81-87,  93,  94,  225,  321 

Fuchs,  154-157,  176,  193,  380 

Fuchs  &  Gehlen,  357,  359 

Fullon,  v.,  362,  425 


G 

Galbraith,  373 

Gans,  210,  211 

Garret,  393 

Gehlen  ;  see  Fuchs  &  Gehlen 

Genth,  369,  385,  391,  395,  399 

Gerhardt,  48,  230 

Geuther,  293 

Gibbs,  W.,  15,  96,  100-102,  221 

Gill,  408 

Gintl,  395,  403 

Gittelson,  265 

Giwartowsky,  380 

Glan,  P.,  228 

Gluhmann,  269 

Gmelin,  136,  146,  150,  322 

Gmelin-Kraut,  256 

Goldschmidt,  V.,  6,  11,  282 

Golowkinski,  4 

Gomberg,  276,  278 

Gooch,  385,  391 

Gorgeu,  24 

Grabe,  246 

Grandeau,  382 

Grauer,  196 

Graw,  401 

Greve,  234 

Groger,  M.,  242,  243 

Groth,  P.,  6,  9,  27-29,  282,  283,  292,  294, 

309,  313,  314 
Griinzweig,  G.,  433 

Guckelberger,  137,  138,  151,  322,  431-434 
Giimbel,  v.,  395,  397,  417 
Gunzert,  230 


NAME   INDEX 


447 


H 


Hagen,  417 

Haidinger,  316 

Hamberg,  387 

Hamm,  v.,  387 

Hammerschlag,  403 

Hantzsch,  266,  267,  276,  278 

Hantzsch  ;   see  Werner  and  Hantzsch 

Hallopeau,  270 

Hardmann,  401 

Hardt,  156,  157 

Hartwall,  378,  385 

Hartwall  &  Herdberg,  378 

Hata,  224 

Hauer,  K.  v.,  371,  373,  393,  397,  399,  419 

421,  425,  427 

Haughton,  373,  413,  415,  425 
Haushofer,  5,  28,  425 
Hautefeuille,  24,  292 
Hauy,  293,  317 
Hawes,  393 
Hebenstreit,  417 

Heddle,  354,  356,  358,  360,  373,  378   385 
387,  389,  391,  393,  397,  399,  401,  403? 
411,  413,  415,  417,  423,  425,  427 
Heinsheimer,  230,  234 
Heldt,  156,  163 
Henry,  C.,  71 
Hentze,  230,  233 

Herdberg  ;  see  Hartwall  and  Herdberg 
Hermann,  311,  354,   360,   362,  374    376 

378,  380,  385,  401,  403 
Hersch,  66 
Herz,  M.,  283 

Herzog,  N.  v.  Leuchtenberg,  401,  403 
Heumann,  137,  147-150,  322,  431,  432 
Heydweiller;  see  Kohlrausch  &  Heyd- 

weiller 

Higgin,  A.  J.,  266,  267 
Hilger,  367 
Hillebrand,  353 
Hintze,  48,  61 
Hirschfeld,  234 
Hofer,  423 
Hoff,  van't,  266,  278,  281,  284,  307    315 

326 

Hoffmann,  146,  322,  415,  427 
Hoffmann,  A.  W.,  434 
Hoffmann,  O.,  208 

Hoffmann,  R.,  137,  138,  147,  152,  322  433 
Hoppe-Seyler,  271 
Horstmann,  230,  312 
Hovestadt,  254 
How,  358 

Howe  ;  see  Penfield  &  Howe 
Hundeshagen,  102,  212 
Hunt,  283,  358,  374,  378,  380,  385,  387 

389,  415,  419,  421,  423,  425 
Hunt,  St.,  4 
Hunter,  J.,  303 


Igelstrom,  365,  371,  399,  401 


Jackson,  360,  413,  415 

Jacobs,  399 

Jacobson,  427 

Jannasch,  54,  296,  391,  410,  421 

Jannasch  &  Calb,  404,  406,  408,  410 

Jannasch  &  Locke,  54 

Jannetaz,  378,  415 

Janowsky,  395,  403 

Jantsch,  131 

Jantzen,  170 

Jewrechow,  373,  425 

Jex,  157,  163,  164 

Jochum,  113 

Jorgensen,  257 

Johnson,  A.,  70 

Jones,  266,  267 

Jordis  &  Kanter,  158,  163 

Jung,  205,  206,  208 

K 

Kanter  ;   see  Jordis  &  Kanter 

Karewski,  234 

Kaul,  H.,  430 

Kehrmann,  17,  20,  99,  102,  278,  321 

Kehrmann  &  Freinkel,  20,  101 

Kekule,  272,  310,  311 

Keller,  425 

Kemp,  413 

Kerndt,  417 

Kersten,  413 

Keyser,  234,  395 

Kiepenheuer,  382 

Killing,  371 
|  Kitasato,  223 
i   Klaproth,  3 

Klein,  96,  97 

Klein,  C.,  317 

Klement,  395,  399,  421,  423 

Klemm,  353 

Klocke,  312 

Knapp,  174,  175 

Knapp  &  Ebell,  150 

Knoblauch,  228,  276 

Knop,  14,  367,  425 

Knorr,  A.,  223 

Kobell,  358,  361,  367,  373,  385,  393,  395 

399,  403 
Koch,  425 
Koch,  E.,  143 
Koch,  Robert,  223 
Koch  &  Uhlenhut,  224 
Konig,  367,  369,  371,  373,  395,  413,  415 
Kohlrausch,  241,  269 
Kohlrausch  &  Heydweiller,  260 
Kohlschiitter,  V.,  257,  266 
Kolbe,  270 
Komonen,  403 
Kosmann,  157,  163,  164 
Kostanecki ;    see  Liebermann,  C.,  &   St. 

Kostanecki 
Koto,  419 
Kraut ;   see  Brandhorst  &  Kraut 


448 


NAME   INDEX 


Kressler,  136 

Kruss,  G.,  &  S.  Oeconomides,  143 

Kulka,  202-206,  232 

Kuntze,  O.,  261 


Lacroix,  374 

Ladenburg,  310,  311 

Lagorio,  401 

Lagus  &  Olckonon,  376 

Landrin,  164 

Lardin,  234 

Lartschneider,  231,  233 

Lasaulx,  v.,  292 

Laspeyres,  354,  355,  371,  423 

Laurell ;   see  Bonsdorff  &  Laurell 

Laurent,  4,  413 

Lawrow,  4 

Le  Bel,  281,  314 

Le  Blanc  &  Noyes,  270 

Le  Chatelier,  157,  158,  163,  196,  197 

Leduc,  163 

Leeds,  380,  389 

Lehmann,  O.,  294,  317 

Lehunt,  371,  421 

Lemberg,  11,  25,  29,  39-44,  47,  56,  57,  59, 

340-352,  358,  369,  376,  380,  417,  423, 

425 

Levy,  M.  ;  see  Fouqe  &  M.  Levy 
Ley,  H.,  229,  260 
Liebe,  387,  389,  393 
Liebermann,  C.,  246 
Liebermann,  C.,  &  St.  Kostanecki,  225 
Liebig,  270 
List,  391 

Locke  ;  see  Jannasch  &  Locke 
Loebell,  435 
Low,  223 
Loew,  O.,  271 
Loretz,  389,  397 
Lory,  425 

Lossen  &  Zander,  312 
Lowry,  259,  266,  267 
Ludwig,  129,  163,  164,  355,  387,  395 
Luedecke,  356 
Lunge,  160,  171 

M 

Mach,  100 

Malaguti ;  see  Brongniart  &  Malaguti 
Mallard,  11,  70,  292,  312,  314 
Mallet,  371 
Maly,  423 
Manchot,  273,  320 
Manchot  &  Reiser,  111,  272 
Marignac,  94,  95,  96,  97,  241,  269,  387, 

389,  391,  401 
Marsh,  356,  358 
Marx,  230 
Massalin,  369 
Masur,  A.,  232 
Mattirolo,  419 
Maumene,  254 
Mauthner,  354 


Mellor  &  Holdcroft,  6,  29,  107,  110,  111, 
112,  113,  119,  120,  121,  122,  123,  128 

Melville,  393 

Mene,  C.,  106 

Merian,  413 

Merz,  387 

Metschnikoff,  223 

Meyer,  A.,  163,  164 

Meyer,  E.  v.,  282 

Meyer-Mahlstadt,  157 

Meyer,  R.,  311 

Meyer,  V.,  272 

Michaelis,  17,  132,  156,  160,  163,  164,  175, 
178,  186,  196 

Miller,  200,  221,  232 

Minor  ;   see  Penfield  &  Minor 

Mitscherlich,  4,  293,  294,  316,  323 

Morgenstern,  199,  202-206,  218 

Moroziewicz,  23 

Morveau,  Guy  ton,  136 

Miiller.  368,  373 

Muir,  382 

Muthmann,  307,  308 

Mylius  &  Foster,  237 

N 

Nanke,  354 
Nef,  276 
Neminar,  401 
Nernst,  228,  229,  266,  276 
Newberry  Bros.,  157,  163,  164 
Nietzki,  R.,  142,  143,  146 
Nordenskiold,  376,  378 
Noyes  ;  see  Le  Blanc  &  Noyes 


Obermayer,  397 

Odling,  4,  6 

Oeconomides,  S.,  143 

Ohl,  A.,  427 

Olckonon  ;   see  Lagus  &  Olckonon 

Oppenheim,  256 

Oppler,  235 

Ortmann,  401 

Ostwald,  Wilhelm,  16,  24,  178,  187,  188, 

227,  228 
Ottolenguis,  232 


P.,  J.J.,  319 

Pagenstecher,  234 

Parmentier,  96,  97,  241,  321 

Partsch,  230 

Paschkis,  H.,  221 

Passmore,    F.  ;      see    Fischer,    E.,    &    F. 

Passmore 
Pasteur,  224,  313 
Paternos,  259 
Pawel,  232,  233 
Payne,  423 
Pearse.  393,  401 
Pechard,  98,  101,  102,  321 
Peckert,  230 
Pelouze,  242,  243 


NAME   INDEX 


449 


Penfield  &  Howe,  306 

Penfield  &  Minor,  54 

Penfield  &  Sperry,  405,  417 

Pernossi  ;    see  Fermi  &  Pernossi 

Perkin,  W.  H.,  and  Kipping,  E.  S.,  309 

Petersen,  413 

Petrusky,  K.,  434 

Pettenkoffer,  154 

Petterson,  O.,  317 

Pfaff,  234 

Philipp,  137,  146,  147,  322,  431,  432,  433 

Piccard,  393 

Pisani,  365,  371,  376,  389,  397,  415, 417, 419 

Port,  230 

Proust,  302-304 

Priickner,  136 

Pufahl,  19,  100,  389 

Pukall,  W.,  7,  111,  117-120 


R 

Raimondi,  413 
Rammelsberg,  C.,  4,  6,  14,  27,  28,  55,  99, 

101,  295,  300,  305,  306,  353,  355,  369, 

375,  380,  382,  391,  393,  397,  399,  405, 

406,  408,  410,  423,  427 
Ramsay,  William,  281 
Ramsay  <fe  Aston,  259 
Raoult,  266 
Rath,  G.  v.,  374,  376,  378,  380,  382,  413, 

415,  417,  419,  421,  423,  425,  427 
Rawitzer,  201,  202,  206,  208 
Re,  H.,  274 

Rebbufat,  163,  164,  196 
Recoura,  262-264,  323 
Reissner,  230,  232 
Remsen,  257 
Renard,  354,  361,  373 
Rennie,  E.  H.,  266,  267 
Retgers,  298,  300,  302 
Reusch,  312,  313,  316 
Reymond,  De  Bois,  326 
Ricciardi,  421 
Richardson,  158,  163 
Richter,  113,  126,  127,  131,  155,  175 
Riehter,  Rob.,  202,  232,  354 
Rickmann,  431,  432,  433 
Riegel.  356 

Rieke,  R.,  110,  111,  113,  134,  371 
Riesen,  van,  401 
Riggs,  404,  406,  408,  419 
Rinne,  70 

Ritter,  137,  151,  433 
Rivot  &  Chatoney,  156,  163,  164 
Rocholl,  419 
Roelig,  265 
Roepper,  373 
Rohland,  136,  157,  165 
Rosam,  395 
Rose,  4,  316,  317 
Rose  &  Hampe,  250 
Rosenheim,  271 
Rostaing,  208 
Rumpf,  365,  387 
Rutheford  &  Soddy,  274 

2   G 


Sachs,  230,  233 

Sachse,  311 

Sackur,  278 

Sadtler,  358 

Safarik,  5,  324 

Salomon,  382 

Sandberger,  397,  405 

Sanderson,  199 

Santerson,  399 

Sauer,  169,  369,  407 

Sawtschenkow,  6 

Schachtel,  233,  235 

Schafer,  278 

Schafhaiitl,  375 

Scharizer,  404,  406,  408 

Scharpless,  369 

Scheerer,  6,  354,  355,  371,  415 

Scheff,  271 

Scheffer,  G.,  433,  434 

Scheuer,  230 

Schiefferdecker,  362 

Schiff,  4,  312 

Schiffner,  196 

Schlaepfer,  385,  387,  401 

Schluttig,  W.,  77 

Schmid,  E.  E.,  358,  397,  421 

Schmidt,  234,  311,  427 

Schmidt  &  Unger,  158,  159,  169 

Schneider  ;   see  Clarke  &  Schneider 

Schnerr,  K.  H.,  55,  355 

Schnorf,  413 

Schonaich-Carolath,  157 

Schott,  157,  158,  160,  190,  192,  193,  198, 

238,  240,  243 
Schrauf,  A.,  281,  391 
Schreiber,   202,   203,   204.  206,   219,   225, 

230-233,  235 
Schroder,  362 
Schiitz,  M.,  142 
Schulek,  234 

Schuljatschenko,  155,  156,  195 
Schulte,  230 
Schultze,  H.,  300,  302 
Schuster,  292,  295 
Schwager,  367 
Schwarz,  236,  408 
Schweizer,  389 
Searle,  A.  B.,  104,  109,  112,  128,  133,  134. 

161 
Seger,  108,  124,  127-130,  132,  133,  135, 

135,  240,  251,  252 
Segeth,  419 
Selkmann,  376 
Selowsky,  230 
Seneca,  417 

Shepherd ;  see  Allen  &  Shepherd 
Seidler,  211 
Siem,  226 

Siemiradzki,  415,  419 
Silber,  P.,  25,  53,  62,  139,  321 
Silbermann,  230,  232 
Simmonds,  111 
Simonis,  130 


450 


NAME   INDEX 


Singer,  11 

Sipocz,  A.,  361,  362,  371,  378,  391,  423 

Smith,  L.,  361,  369,  405,  413 

Smith  &  Brush,  369,  385,  387,  417 

Smithson,  3,  10 

Sobolew,  16 

Soddy,  274,  279 

Soddy  ;   see  Rutheford  &  Soddy 

Soenderop,  256 

Sohncke,  285,  289,  316 

Sommaruga,  E.  v.,  134,  427 

Sommerfeldt,  70,  72 

Sommerland,  353,  406 

Spencer  &  Newberry,  163 

Sperry  ;    see  Penfield  &  Sperry 

Sprenger,  17,  101,  102 

Stadeler,  4,  55 

Stark,  J.,  274 

Stas,  237 

Stein,  136,  230 

Steinmann,  395 

Stockar-Escher,  354,  355 

Stolzel,  C.,  150,  151 

Stohmann,  310 

Stremme,  319,  323 

Streng,  4,  415,  419,  425 

Strumpel,  202 

Struve,  95,  403,  413 

Suida,  360 

Sutherland,  259 

Swiatkowski,  419 

Szilasi,  137,  148,  149,  322,  391,  431,  432 


Tachenius,  3 

Tammann,  G.,  259,  268,  300,  301 

Teichek,  v.,  181,  435 

Telek,  387 

Thomson,  259,  311 

Thomson,  356,  365,  380,  419 

Thoreld,  367 

Thugutt,  St.  J.,  11,  25,  27,  28,  44,  45,  47, 

52,  53,  58-62,  64,  152,  198,  321 
Tickle  ;   see  Collie  &  Tickle 
Tornebohm,  158 
Topsoe,  300,  302 
Tournier  d'Albe,  266,  267 
Traube,  397 

Tschermak,  5,  6,  27,  295,  300,  391,  421 
Tutton,  A.  E.,  283,  312 


U 

Uhlenhut ;  see  Koche  &  Uhlenhut 

Unger,  136 

Unger  ;  see  Schmidt  &  Unger 


V 

Vaillant,  266,  267 

Valentino,  419 

Varrentrapp,  136,  371,  391,  403.  427 

Vaubel,  311 


Vernadsky,  5,  6,  23,  27,  28,  30,  47,  106, 

165,  324,  325 

Vespignani ;   see  Carrara  &  Vespignani 
Vicat,  154 

Villiger  :   see  Baeyer  &  Villiger 
Vogel,  H.  W.,  143,  228 
Vogt,  284,  378 
Vohl,  430 
Vossius,  234 
Vucnik,  284 
Vuylsteke,  399 


W 

Wacher,  234 

Wagner,  G.,  362 

Walden,  278 

Walker,  278 

Walkers,  259 

Waltershausen,  v.,  419,  421 

Wartha,  5,  6,  28,  387,  391 

Watson,  J.  A.,  266,  267 

Weber,  240 

Websky,  397 

Wedel,  425 

Wedl,  234 

Wege,  218,  233,  235 

Werner,  A.,  257,  258,  266,  278,  326 

Werner  &  Hantzsch,  282 

Weryecke,  van,  403 

Whitney,  262,  263,  265,  323,  362 

Wild,  230 

Wilk,  354,  378,  391,  423 

Williams,  421,  423 

Winkler,  154,  155,  160,  163,  176,  234 

Wislicenus,  J.,  281 

Witt,  O.  N.,  142,  246 

Wittstein,  382 

Wohler,  250 

Woltzien,  4 

Woitschach,  395 

Wolff,  374,  376,  380 

Wolff,  C.,  230 

Wollemann,  417 

Wulf,  355 

Wulff,  314 

Wurtz,  4,  380,  401 

Wymper,  268 

Wyrouboff,  300,  302 


Zander  ;   see  Lossen  &  Zander 

Zellner,  367 

Zeltner,  146 

Zenker,  21 

Zeynek,  R.  v.,  395,  397 

Ziem,  234 

Ziemjatschewsky,  24 

Zinn,  N.  v.,  403 

Zsigmondy,  157 

Zulkowski  24,  28,  160,  163,  164,  176,  177, 

181,  182,  193,  236,  237,  241,  243,  248, 

249-251,  435,  436 


SUBJECT  INDEX 


A-aluminosilicates,  165,  197 

A-cements,  214,  235 

A-cements,  toxic  action  of,  219 

A-sodalites,  153 

a-complexes,  76,  78 

a-hydrogen,  197 

a-hydroxyl,  65,  165,  210 

a-  or  2-hydro-aluminosilicates,  142 

a-vanadomolybdic  anhydrides,  79 

Acid  anhydrides,  141 

Acid,  ferrosulphuric,  264 

Acid  nature  of  silica,  4 

Acid-reacting  salts,  228 

Acid- water,  65 

Acidity  of  clays,  106 

Acido-philism,  210 

Acids,  action  of,  on  hydraulic  lime,  194 

Acids,  action  of,  on  cement,  189 

Acids,  chromo-sulphuric,  263 

Acids,  complex,  15 

Acids,  constitution  of,  268 

Acids,  water  of  crystallisation  in,  265 

Actinolite,  300 

Aggregation,  states  of,  294 

Alabaster  glass,  237 

Albite,  9,  46,  64,  295 

Alite,  158 

Alkalies,  action  of,  on  cements,  189,  194 

Alkaline    carbonates,    action  of,    on    ce- 
ments, 193 

Allophane  group,  104,  108,  109 

Alum  potash,  315 

Alums,  water  in,  262 

Alumina,  acid  nature  of,  23 

Aluminium  atoms,  variable  behaviour  of, 
25 

Aluminium  in  silicates,  role  of,  5 

Aluminophosphates,  226 

Aluminophosphoric  acids,  222 

Aluminophosphoric  acids  and  nerve-fibres, 
225 

Aluminosilicates,  6,  7,  56,  75,  90,  139,  169, 
175,  261,  319 

Aluminosilicates,  attraction  of,  for  acids 
and  bases,  210 

Aluminosilicic  acids,  6,  62,  103,  165 
Ammonias,  metallic,  17,  256 
Ammonium  compounds,  299,  306,  317 
Ammonium  salts,  299 
Amphibole,  300 
Amphichromatophilism,  212 
Analcime,  9,  11,  14,  25,  45,  46,  47,  72,  176 
Analysis,  rational,  322 
Andalusite,  9 


Andesite,  24,  62 
Anhydrobasic  salt,  166 
Anorthite,  5,  47,  295 
Apatite,  291 
Aragonite,  291,  293 
Archid  hypothesis,  273 
Ardennite,  29,  75 
Arsenates,  291,  294,  307 
Arsenic  acid,  294 
Arseno-compounds,  93 
Arsenomolybdates,  18,  93 
Ascharite,  291 
Atomic  complexes,  165 
Atoms,  constitution  of,  274 
Atoms,  transmutation  of,  281 
Atoms,  valencies  of,  275 
Avasite,  78 
Aventurine  glass,  249 
Axes,  chemical,  286 

B 

Base-prognoses,  73 

Base-water,  65 

Basic  group,  effect  of,  95,  108 

Basic  salts,  167 

Basis-isomerism,  63 

Baso-philism,  210 

Belite,  158 

Benzene,  structural  formula  of,  309 

/3-complexes,  76,  95 

/3-hydroxyls,  65 

/3-vanadomolybdates,  79 

Binding  materials,  153 

Bischof  &  Richter's  law,  127 

Blue  Staffordshire  bricks,  135 

Boronatrocalcite,  291 

Boron  compounds,  76,  77 

Boulder  clay,  108 

Burned  clay,  colour  of,  135 

Burning  clays,  111 


Cadmium  compounds,  299 

Calcite,  293 

Calcium  aluminosilicates,  169,  200 

Calcium  carbonate,  291 

Calcium  compounds,  317 

Calcium  hydrate,  183 

Calcium  sulpho-aluminates,  196 

Calcspar,  291 

Carbon  and  silicon  compared,  1 

Carbon  compounds,  270 

Carbonates,  action  of,  on  cements,  193 

Carbonic  acid,  293 


451 


452 


SUBJECT   INDEX 


Carbonic  acid,  action  of,  on  hardened 
mortar,  193 

Carbonic  acid  in  mortar,  190 

Celite,  158 

Cement,  action  of  salts  on,  160 

Cement,  action  of  sulphates  on,  196 

Cement,  action  of  water  on,  197 

Cement,  effective  substances  in,  157 

Cement,  Fletcher's,  199 

Cement  formulae,  179 

Cement  prognoses,  193 

Cement,  swelling  of,  196 

Cements,  153,  322 

Cements,  action  of  acids  and  alkalies  on, 
189,  194 

Cements  and  sea  water,  195 

Cements,  cracking  of,  175,  198 

Cements,  dental,  199 

Cements,  expansion  of,  175 

Cements,  hardening  constituents  of,  164 

Cements,  hardening  of,  177 

Cements,  heat  development  in,  187 

Cements,  hydration  of,  181 

Cements,  isomeric,  195 

Cements,  regenerated,  186 

Cements,  silicate,  199 

Centralisers,  245 

Centralisers,  zinc  phosphate,  199 

Chabasite,  47 

Chemical  axes  of  crystals,  286 

Chemical  constitution  of  Portland  ce- 
ments, 165 

China  clay  (see  Kaolin),  110 

Chlorite,  47 

Chlorite  ring,  325 

Chlorosodalite,  59,  64 

Chondrodite,  306 

Chromates,  300,  302 

Chrome  alum,  263 

Chromophores,  245 

Chromo-sulphuric  acids,  263 

Chromotropy,  278 

Clay,  colloids  in,  134 

Clay,  colour  of,  135 

Clay,  iron  oxide  in.  135 

Clay,  plasticity  of,  133 

Clay,  red-burning,  135 

Clay  substance,  106 

Clay,  water  of  constitution  in,  134 

Clayite,  128 

Clays,  6,  7,  168,  176,  322 

Clays,  constitution  of,  102 

Clinker,  158 

Clinohumite,  306 

Clintonite  group,  49,  300 

Cobalt  compounds,  256,  292,  299,  306 

Colemanite,  291 

Colloidal  properties  of  cements,  162 

Colloids,  244 

Colour  of  bricks  and  clay,  135 

Combined  water,  65,  321 

Complex  acid  theory,  62 

Complexes,  165 

Composition  of  clays  and  melting  point,  129 


Conductivity,  227 
Constitution  of  aluminosilicates,  7 
Constitution  of  silicates,  3 
Constitution  of  slags,  169 
Co-ordination  law,  Werner's,  326 
Copper  ruby  glass,  249 
Cracking  of  cements,  175,  198 
Cristobalite,  292 
Cryophillite,  27 

Crystalline     form     and     chemical     com- 
position, 282 
Crystallography,  282 
Crystal  molecule,  283 
Crystals,  angles  of,  294 
Crystals,  optical  properties  of,  312 
Crystals,  structure  of,  285,  289,  326 
Cyanogen  compounds,  256 

D 

Decolouration  of  glass,  246 

Density,  change  in,  168 

Dental  cements,  199,  322 

Dental  stopping,  characteristics  of,  200 

Dentistry,  relation  of  H.P.  theory  to,  199 

Depression  of  thermometer,  239 

Desmine,  47,  48,  70,  71 

Devitrification  of  glass,  241 

Di-carbonic  acid,  293 

Diffusibility  of  A-  and  2-cements,  235 

Dimorphism  of  CaCO3,  293 

Disdynamised  compounds,  108 

Dissociation  theory,  266 

Double  salts,  11,  12,  16 

Dualism,  chemical,  305 

Dyes,  246 

Dye-stuffs,  212 

Dynamisation  theory,  168 

Dynamised  compounds,  108 

E 

Effective  substances  of  cement,  157 
Elaolite,  9 
Elaolite-syenite,  59 
Endlichite,  291 
Enamels,  236 
Enantiomorphism,  313 
Enantiomorphous  crystals,  313 
Entpolymerisation,  170 
Epidote,  46,  47,  53,  301 
Epistilbite,  66,  68 
Expansion  of  cements,  175 


Faujasite,  66,  68 

Felite,  158 

Felspar,  5,  53,  58,  62,  64,  176,  294 

Felspar  group,  51 

Felspars,  formulae  of,  297 

Ferric  sulphide,  292 

Ferrocyanides,  257 

Ferrosulphuric  acid,  264 

Fire  resistant  quotient  (Bischof),  126 


SUBJECT   INDEX 


453 


Fire  resistant  quotient  (Seger),  128 

Fletcher's  cement,  199 

Fluorine  compounds,  55 

Forecite,  66,  69 

Formulae,  calculation  of,  48 

Formulae  of  porcelain  cements,  215 

Franklandite,  291 

Free  lime  in  cement,  155 


G 

7-hydroxyl,  65 

Genetic  relationship,  10,  14,  22,  40,  43,  47, 

297,  298 
Genetic    relationship    between    Portland 

and  slag  cements,  160 
Geometrical  constants,  305 
Glass,  Thuringian,  238,  240 
Glasses,  236 
Glasses,  coloured,  243 
Glasses,  constitution  of,  239 
Glasses,  formulae  of,  254 
Glazes,  236 

Glazes,  formulae  of,  254 
Granite,  47,  56 
Gypsum,  action  of,  on  cement,  196 


Hardening  constituents  of  cements,  164 
Hardening  of  cements,  153 
Hardening  of  dental  cements,  213 
Hardening  of  porcelain  cements,  205,  208, 

212 

Hardening  of  Portland  cements,  173 
Hardening  of  Portland  cements,  causes  of, 

177 

Hardening,  regulation  of,  217 
Hardening,  secondary,  of  cements,  193 
Heat  development  in  hardening  cements, 

187 

Heat  on  clay,  effect  of,  109  to  130 
Heat  resistance  and  composition,  126 
Heulandite,  47,  66,  67,  70 
Hexite,  30 

Historical  review  of  cements,  153 
Historical  review  of  ultramarines,  136 
Historical  survey,  3 
Howlite,  77 
Humite,  306 
Hydrated  limes,  183 
Hydration  of  porcelain  cements,  213,  216 
Hydration  of  Portland  cements,  181 
Hydration  phase,  173 
Hydraulic  binding  materials,  153 
Hydraulic  limes,  153,  183,  188,  193 
Hydraulic  limes,  action  of  acids  on,  194 
Hydraulic  modulus,  168 
Hydraulite,  153 

Hydro-aluminosilicates,  106,  210,  261 
Hydrobasic  groups,  209 
Hydrobasic  salt,  166 
Hydroborasite,  291 
Hydroferrosulphates,  261 
Hydrohexites,  32 


Hydronephelite,  9,  65,  67 
Hydro-pentites,  33 
Hydrous  aluminosilicates,  65 
Hydroxide  water,  194 
Hydroxyl  groups,  51,  52,  53,  72 
Hygroscopicity  of  clay,  123 


Ice,  polymeric  forms  of,  259 
Iron  compounds,  78,  299,  301 
Isomeric  aluminosilicates,  64 
Isomeric  lime  and  magnesia,  175 
Isomerism,  63,  113 
Isomers  of  silicate  cements,  195 
Isomorphism,  294 
Isomorphous  mixtures,  13,  26,  296 

K 

Kaliborite,  291 
Kampylite,  291 
Kaolin,  6,  7,  9,  10,  25,  44,  46,  47,  52,  90, 

113,  139,  165,  181 

Kaolin,  acido-  and  baso-philism  of,  212 
Kaolin,  amphichromatophilism  of,  212 
Kaolin,  constitution  of,  212 
Kaolin  lakes,  212 
Kaolinates,  118 
Kaolinic  acid,  6,  111,  115 
Kaolinisation,  117 
Kaolinite,  110 
Krypolite,  10 


Labradorite,  295 

Lakes,  212 

Lardellerite,  291 

Laumontite,  46,  47,  65,  66,  91 

Leucite,  9,  46,  176 

Lime,  action  on  bond  in  cements,  194 

Lime- clay  mixtures,  181 

Lime  compounds,  306 

Lime,  free,  in  cement,  155 

Lime,  hardening  of,  174 

Lime,  hydraulic,  193 

Lime  in  cements,  removal  of,  193 

Lime,  isomeric,  175 

Lime,  proportion  removable  from  cement, 

160 

Lime,  separation  of,  in  cements,  190 
Lime-silica  mixtures,  hardening  of,  176 
Limes,  hydraulic,  action  of  acids  on,  194 
Lud wig's  chart,  128 

M 

Magnesia  compounds,  306 
Magnesia,  isomeric,  175 
Magnesia,  slaking  of,  175 
Magnesium  silicate,  176 
Manganese  compounds,  299,  306 
Marcasite,  292 
Margarite,  10 
Masonry,  destruction  of,  195 


454 


SUBJECT   INDEX 


Melting  point,  168 

Melting  point  and  composition,  129 

Melting  point  of  clays,  109,  124 

Melting  point  of  silicates,  131 

Mesolites,  57 

Metal-ammonias,  256 

Metal-ammonium  salts,  17 

Mica,  9,  58,  60,  300,  313 

Mica  group,  49 

Mica  ring,  325 

Microcline,  64 

Micrographic  examination  of  cements,  158 

Micrographic  study  of  hardening,  178 

Milarite,  78 

Mimetesite,  291 

Mix-crystals,  298 

"Mixture,"  112 

Mixture  theories,  6,  26,  62,  163,  253,  295, 
298 

Mixture  theory  of  cements,  158 

Modulus,  hydraulic,  168 

Molasses,  211 

Molecular  compound,  12 

Molecular  core,  298 

Molecular  volumes,  317 

Molecular  weight  of  slags,  171 

Molecular  weights  of  crystals,  285 

Molybdates,  16,  300,  302 

Molybdenum  compounds,  78,  79 

Mordennite,  78 

Mortar,  156 

Mortar,  action  of  CO2  on,  193 

Muscovite,  9,  45,  46,  47 


N 

Natrolite,  9,  46,  47,  59,  66,  70,  91,  176 
Nepheline,  6,  9,  25,  46,  52,  61,  62 
Nepheline  hydrate,  52,  58,  59 
Neptunite,  48 
Nerve-fibres  and  aluminophosphoric  acids, 

225 

Nerve-fibres,  chemical  constitution  of,  224 
Nerve-substance,  reactions  of,  222 
Neurotropism  of  aluminophosphoric  acids . 

222 

Nickel  compounds,  292,  299,  306 
Nomenclature  of  silicates,  113,  114 
Nontronite,  136 
Nordenskioldite,  76 
Norsean,  59 
Nucleus,  molecular,  298 


Oligoclase,  295 
Olivine,  47 
Opals,  106 

Optical  properties  of  crystals,  312 
Optically  active  crystals,  313 
Orthochlorite  group,  50,  300 
Orthoclase,  9,  12,  27,  46,  64,  295 
Oxygen,  valency  of,  109 
Oxyphilism,  212 


^andermite,  291 
Daraleucaniline,  246 
Parameters,  307 
Phakelite,  27 
Pelinite,  128 
Pentite,  32 
Permutites,  210 
Petalite,  23 
Phillipsite,  47 

Phosphates,  291,  294,  300,  307 
Phosphoric  acid,  294 
Phosphorous  compounds,  269,  271,  293 
Phosphotungstates,  20 
Pigments  with  hydraulic  properties,  198 
Plaster  of  Paris,  action  of,  on  cement,  196 
Plasticity  of  clay,  133,  322 
Polymerisation,  113,  168 
Polymerisation  of  gas-molecules,  283 
Polymorphism,  290 
Polyspharite,  291 
Porcelain  cements,  199 
Porcelain  cements,  chemical  constitution 

of,  209 

Porcelain  cements,  formulae  of,  215 
Porcelains,  236 
Porcelains,  formulae  of,  254 
Porphyrexides,  277 
Porpora  glass,  248 
Portland  cement,  153,  322 
Portland  cement,  action  of  water  on,  197 
Portland  cement  and  sea  water,  195 
Portland  cement  formulae,  179 
Portland  cement,  hydration  of,  181 
Portland  cements,  constitution  of,  165 
Portland  cements,  hardening  of,  173,  177 
Potash  compounds,  306 
Potash  felspar,  53,  64 
Potash  mica,  58,  59,  60 
Potash  nepheline,  58 
Potassium  compounds,  300,  317 
Potassium  silicotungstate,  95 
Prehnite,  45,  47 
Prismatine,  10 
Prolektite,  306 

Pseudomorphous  processes,  45 
Ptiolite,  78 
Puzzolans,  153,  176 
Pyrite,  292 
Pyromorphite,  291 
Pyrophillite,  46 


Quartz,  176 

Quicklime,  slaking  of,  174 


R 

Racemic  acid,  313 
Radio-activity,  causes  of,  279 
Rational  analysis,  107,  108 
Red-burning  clays,  135 
Refractoriness  and  composition,  126 


SUBJECT   INDEX 


455 


Refractory  index,  130 
Regenerated  cements,  186 
Resistance  to  alkalies  of  slags,  160 
Ring-isomerism,  64 
Ring-prognoses,  74 
Ring-water,  72 
Roman  cement,  153 
Rosaniline,  246 
Rubidium  compounds,  317 
Ruby  glass,  249 

S 

2,  60,  152 

2-aluminosilicates,  197 

2-cements,  213,  227,  235 

2-hydro-aluminosilicates,  142 

2-sodalites,  153 

2-ultramarines,  215 

Saliva,  action  of,  on  cements,  218 

Sapphirin,  23,  76 

Scapolite,  62 

Scapolite  group,  50 

Scolecite,  66,  69,  91 

Sea  water,  action  of,  on  cements,  195 

Seger  cones  and  temperatures,  129,  130 

Setting  of  cements,  153 

s-hydroxyls,  65,  165,  209,  210 

Side-chains,  305 

Silica,  3,  291 

Silica-lime  mixtures,  hardening  of,  176 

Silica,  precipitated,  7 

Silica,  soluble,  154,  156,  189 

Silica,  separation  from  ultramarine,  151 

Silicate  cements,  199 

Silicate  cements,  isomers  of,  195 

Silicate- water,  186,  194 

Silicic  acid,  3 

Silico-aluminic  acid,  6 

Silico  hydrates,  8 

Silico-molybdate,  16 

Silico-tungstates,  94 

Sillimanite,  110 

Sintering  point,  159 

Skelezite,  47 

Slag  cement,  153 

Slags,  160,  169 

Slags,  action  of  alkali  on,  172 

Slags,  composition  of,  170,  171 

Soda  felspar,  64 

Sodalites,  12,  25,  42,  43,  46,  52,  59,  60,  65, 

152,  153,  198 

Sodium  alumino-lactate,  226 
Sodium  aluminosilicate,  139 
Sodium  nepheline  hydrate,  59 
Sodium  orthoclase,  64 
Sodium  phosphate,  293 
Sodium  s-kaolinate,  116,  118 
Softening  point  and  composition,  132 
Softening  points,  129 
Softening  water,  211 
Solid  solutions,  71,  157,  159,  253,  305 
Soluble  silica,  154,  156,  189 
Spectrum  analysis,  228 
Spinels,  4 


Steatite,  176 

Stereo-chemical  theories,  criticism  of,  281 

Stereo-hexite   and   stereo-pentite   theory, 

286 

Stilbite,  66,  68 
Strontium  carbonate,  291 
Strontium  carbonates,  306 
Sugar,  inversion  of,  229 
Sugar  recovery,  211 
Sugars,  formation  of,  271 
Sulphides,  292 
Sulpho-aluminates,  196 
Sulphonate  groups  in  ultramarines,   141, 

151 

Sulphonates,  141,  151 
Sulphonates,  action  of,  on  cements,  196 
Sulphonates  as  chromophores,  142 
Sulphur,  292 

Sulphuric  acid  ;  action  on  clays,  107 
Summary,  318 
Syntagmatite,  300 


Talc,  176 

Tartaric  acid,  313 

Tellurium  compounds,  317 

Thermo-chemical  studies  of  hydration,  187 

Thermodynamics,  law  of,  71 

Thermometer  depression,  239 

Thomsonite,  67 

Tin  compounds,  76 

Titanic  oxide,  292 

Topaz,  54,  210 

Topical  parameters,  307 

Tourmaline,  24,  47,  75,  295 

Tourmaline  group,  50 

Toxic  action  of  the  .4 -cements,  219 

Trass,  153,  176 

Tri-calcium  silicate,  158 

Tridymite,  292 

Tungstates,  18 

Tungsten  compounds,  20,  24,  78,  81 

Type  theory,  4 

U 

Ultramarines,  59,  136,  165,  322 
Ultramarines  and  sodalites,  152 
Ultramarines,  composition  of,  143 
Ultramarines,  constitution  of,  212 
Ultramarines,  effect  of  heat  on,  150 
Ultramarines,  isomeric,  147 
Ultramarines,  vitrification  of,  150 
Uranium  compounds,  306 
Urano -acetates,  306 


Valencies,  275,  289,  294 

Vanadates,  291 

Vanadinite,  291 

Vanadium  compounds,  20,  75,  79 

Vitrification  of  clay,  109 

Vitrification  of  ultramarines,  150 


456 


SUBJECT   INDEX 


w 


Water,  combined,  65,  72,  109,  110 
Water  of  constitution,  4,  51,  53,  65,  95, 

104,    108,    109,    116,    134,    152,    305, 

321 
Water  of  crystallisation,  59,  65,  71,  103, 

108,  186,  259,  305,  321 
Water  of  hydration  in  cements,  181,  186 
Water   of    silication  (see    Silicate-water), 

186 


Water-separation  phases,  71 
Water,  softening,  211 


Zeolites,  47,  65,  154,  210,  314 
Zinc  aluminophosphates,  226 
Zinc  compounds,  299,  306 
Zinc  phosphate  cements,  199 
Zinnwaldite,  26 


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Brew,  W.     Three-Phase  Transmission 8vo,  *2  oo 

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Briggs,   R.,  and  Wolff,  A.   R.     Steam-Heating.     (Science   Series   No. 

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Bright,  C.     The  Life  Story  of  Sir  Charles  Til  on  Bright 8vo,  *4  50 

Brislee,  T.  J.     Introduction  to  the  Study  of  Fuel.     (Outlines  of  Indus- 
trial Chemistry.) 8vo,  *3  oo 

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Eroughton,  H.  H.     Electric  Cranes  and  Hoists *9  oo 

Brown,  G.     Healthy  Foundations.     (Science  Series  No.  80.) i6mo,  o  50 

Brown,  H.     Irrigation 8vo,  *5  oo 

Brown,  Wm.  N.     The  Art  of  Enamelling  on  Metal i2mo,  *i  oo 

Brown,  Wm.  N.     Handbook  on  Japanning  and  Enamelling i2mo,  *i  50 

—  House  Decorating  and  Painting i2mo,  *i  50 

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6       D.  VAN  NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG 

Bruhns,  Dr.    New  Manual  of  Logarithms 8vo,  cloth,  2  oo 

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Buel,  R.  H.     Safety  Valves.     (Science  Series  No.  21.) i6mo,  o  50 

Bulman,  H.  F.,  and  Redmayne,  R.  S.  A.     Colliery  Working  and  Manage- 
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Burns,  D.     Safety  in  Coal  Mines. i2mo,  *i  oo 

Burstall,  F.  W.    Energy  Diagram  for  Gas.     With  Text 8vo,  i  50 

Diagram.     Sold  separately *i  oo 

Burt,  W.  A.    Key  to  the  Solar  Compass i6mo,  leather,  2  50 

Burton,  F.  G.    Engineering  Estimates  and  Cost  Accounts i2mo,  *i  50 

Buskett,  E.  W.    Fire  Assaying i2mo,  *i  25 

Butler,  H.  J.     Motor  Bodies  and  Chassis 8vo,  *2  50 

Byers,  H.  G.,  and  Knight,  H.  G.     Notes  on  Qualitative  Analysis  ....  8vo,  *i  50 

Cain,  W.    Brief  Course  in  the  Calculus i2mo,  *i  75 

Elastic  Arches.     (Science  Series  No .  .  48.) i6mo,  o  50 

—  Maximum  Stresses.     (Science  Series  No.  38.) i6mo,  o  50 

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i6mo,  o  50 
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(Science  Series  No.  42.) i6mo,  o  50 

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—  Symbolic  Algebra.     (Science  Series  No.  73.) i6mo,  o  50 

Campin,  F.    The  Construction  of  Iron  Roofs 8vo,  2  oo 

Carpenter,  F.  D.    Geographical  Surveying.    (Science  Series  No.  37.).i6mo, 

Carpenter,  R.  C.,  and  Diederichs,  H.    Internal  Combustion  Engines. .  8vo,  *5  oo 

Carter,  E.  T.     Motive  Power  and  Gearing  for  Electrical  Machinery .  8vo,  *5  oo 

Carter,  H.  A.    Ramie  (Rhea),  China  Grass i2mo,  *2  oo 

Carter,  H.  R.     Modern  Flax,  Hemp,  and  Jute  Spinning 8vo,  *3  oo 

Cary,  E.  R.     Solution  of  Railroad  Problems  with  the  Slide  Rule.  .  i6mo,  *i  oo 

Cathcart,  W.  L.     Machine  Design.     Part  I.  Fastenings 8vo,  *3  oo 

Cathcart,  W.  L.,  and  Chaffee,  J.  I.     Elements  of  Graphic  Statics .  .  .8vo,  *3  oo 

—  Short  Course  in  Graphics i2mo,  i  50 

Caven,  R.  M.,  and  Lander,  G.  D.     Systematic  Inorganic  Chemistry. i2mo,  *2  oo 

Chalkley,  A.  P.     Diesel  Engines 8vo,  *3  oo 

Chambers'  Mathematical  Tables 8vo,  i  75 

Chambers,  G.  F.     Astronomy i6mo,  *i  50 

Charnock,  G.  F.    Workshop  Practice.     (Westminster  Series.) .  .  .8vo  (In  Press.) 

Charpentier,  P.     Timber * 8vo,  *6  oo 

Chatley,  H.    Principles  and  Designs  of  Aeroplanes.     (Science  Series 

No.  126) i6mo,  o  50 

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—  Gyrostatic  Balancing 8vo,  *i  oo 

Child,  C.  D.     Electric  Arc 8vo,  *2  oo 

Child,  C.  T.     The  How  and  Why  of  Electricity i2mo,  i  oo 

Christie,  W.  W.     Boiler-waters,  Scale,  Corrosion,  Foaming 8vo,  *3  oo 

Chimney  Design  and  Theory 8vo,  *3  oo 

Furnace  Draft.     (Science  Series  No.  123.) i6mo,  o  50 

Water:  Its  Purification  and  Use  in  the  Industries 8vo,  *2  oo 


D.  VAN  NOSTRAND    COMPANY'S  SHORT  TITLE  CATALOG      7 

Church's  Laboratory  Guide.     Rewritten  by  Edward  Kinch 8vo,  *2  50 

Clapperton,  G.     Practical  Papermaking 8vo,  2  50 

Clark,  A.  G.     Motor  Car  Engineering. 

Vol.    I.     Construction *3  oo 

Vol.  H.     Design (In  Press.) 

Clark,  C.  H.     Marine  Gas  Engines i2mo,  *i  50 

Clark,  D.  K.     Rules,  Tables  and  Data  for  Mechanical  Engineers  .  .  .8vo,  5  oo 

—  Fuel:  Its  Combustion  and  Economy i2mo,  i  50 

-  The  Mechanical  Engineer's  Pocketbook i6mo,  2  oo 

-  Tramways :  Their  Construction  and  Working 8vo,  5  oo 

Clark,  J.  M.     New  System  of  Laying  Out  Railway  Turnouts izmo,  i  oo 

Clausen-Thue,  W.    A  B  C  Telegraphic  Code.    Fourth  Edition  ..  .i2mo,  *5  oo 

Fifth  Edition 8vo,  *7  oo 

—  The  A  i  Telegraphic  Code 8vo,  *7  50 

Cleemann,  T.  M.     The  Railroad  Engineer's  Practice i2mo,  *i  50 

Clerk,  D.,  and  Idell,  F.  E.     Theory  of  the  Gas  Engine.     (Science  Series 

No.  62.) i6mo,  a  50 

Clevenger,  S.  R.  Treatise  on  the  Method  of  Government  Surveying. 

i6mo,  morocco 2 . 50 

Clouth,  F.  Rubber,  Gutta-Percha,  and  Balata 8vo,  *5  oo 

Cochran,  J.  Concrete  and  Reinforced  Concrete  Specifications 8vo,  *2  50 

-  Treatise  on  Cement  Specifications 8vo,  *i  oo 

Coffin,  J.  H.  C.     Navigation  and  Nautical  Astronomy i2mo,  *3  50 

Colburn,  Z.,  and  Thurston,  R.  H.     Steam  Boiler  Explosions.     (Science 

Series  No.  2.) i6mo,  o  50 

Cole,  R.  S.     Treatise  on  Photographic  Optics i2mo,  i  50 

Coles-Finch,  W.     Water,  Its  Origin  and  Use 8vo,  *5  oo 

Collins,  J.  E.     Useful  Alloys  and  Memoranda  for  Goldsmiths,  Jewelers. 

i6mo,  o  50 

Collis,  A.  G.     Switch-gear  Design 8vo, 

Constantine,  E.    Marine  Engineers,  Their  Qualifications  and  Duties. .  8vo,  *2  oo 

Coombs,  H.  A.     Gear  Teeth.     (Science  Series  No.  120.) i6mo,  o  50 

Cooper,  W.  R.     Primary  Batteries 8vo,  *4  oo 

—  "  The  Electrician  "  Primers 8vo,  *5  oo 

Part  I *i  50 

Part  II *2  so 

Part  HI *2  oo 

Copperthwaite,  W.  C.     Tunnel  Shields 4to,  *g  oo 

Corey,  H.  T.     Water  Supply  Engineering 8vo  (In  Press.) 

Corfield,  W.  H.     Dwelling  Houses.     (Science  Series  No.  50.) ....  i6mo,  o  50 

—  Water  and  Water-Supply.     (Science  Series  No.  17.) i6mo,  o  50 

Cornwall,  H.  B.     Manual  of  Blow-pipe  Analysis 8vo,  *2  50 

Courtney,  C.  F.     Masonry  Dams 8vo,  3  50 

Cowell,  W.  B.    Pure  Air,  Ozone,  and  Water i2mo,  *2  oo 

Craig,  T.     Motion  of  a  Solid  in  a  Fuel.     (Science  Series  No.  49.) .  i6mo,  o  50 

—  Wave  and  Vortex  Motion.     (Science  Series  No.  43.) i6mo,  o  50 

Cramp,  W.     Continuous  Current  Machine  Design 8vo,  *2  50 

Creedy,  F.     Single  Phase  Commutator  Motors 8vo,  *2  oo 

Crocker,  F.  B.     Electric  Lighting.     Two  Volumes.     8vo. 

Vol.    I.     The  Generating  Plant 3  oo 

Vol.  II.     Distributing  Systems  and  Lamps 


8       D.  VAN  NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG 

Crocker,  F.  B.,  and  Arendt,  M.    Electric  Motors 8vo,  *2  50 

Crocker,  F.  B.,  and  Wheeler,  S.  S.     The  Management  of  Electrical  Ma- 
chinery   i2mo,  *i  oo 

Cross,  C.  F.,  Bevan,  E.  J.,  and  Sindall,  R.  W.     Wood  Pulp  and  Its  Applica- 
tions.    (Westminster  Series.) 8vo,  *2  oo 

Crosskey,  L.  R.     Elementary  Perspective 8vo,  i  oo 

Crosskey,  L.  R.,  and  Thaw,  J.     Advanced  Perspective 8vo,  i  50 

Culley,  J.  L.     Theory  of  Arches.     (Science  Series  No.  87.) i6mo,  o  50 

Dadourian,  H.  M.    Analytical  Mechanics i2mo,  *3  oo 

Danby,  A.    Natural  Rock  Asphalts  and  Bitumens 8vo,  *2  50 

Davenport,  C.    The  Book.     (Westminster  Series.) 8vo,  *2  oo 

Davies,  D.  C.     Metalliferous  Minerals  and  Mining 8vo,  5  oo 

Earthy  Minerals  and  Mining 8vo,  5  oo 

Davies,  E.  H.     Machinery  for  Metalliferous  Mines 8vo,  8  oo 

Davies,  F.  H.     Electric  Power  and  Traction 8vo,  *2  oo 

r-  Foundations  and  Machinery  Fixing.     (Installation  Manual  Series.) 

i6mo,  *i  oo 

Dawson,  P.    Electric  Traction  on  Railways 8vo,  *g  oo 

Day,  C.     The  Indicator  and  Its  Diagrams i2mo,  *2  oo 

Deerr,  N.     Sugar  and  the  Sugar  Cane 8vo,  *8  oo 

Deite,  C.     Manual  of  Soapmaking.    Trans,  by  S.  T.  King 4to,  *5  oo 

De  la  Coux,  H.    The  Industrial  Uses  of  Water.    Trans,  by  A  Morris.  8vo,  *4  50 

Del  Mar,  W.  A.    Electric  Power  Conductors 8vo,  *2  oo 

Denny,  G.  A.    Deep-level  Mines  of  the  Rand 4to,  *io  oo 

—  Diamond  Drilling  for  Gold *5  oo 

De  Roos,  J.  D.  C.     Linkages.     (Science  Series  No.  47.) i6mo,  o  50 

Derr,  W.  L.    Block  Signal  Operation Oblong  i2mo,  *i  50 

Maintenance-of-Way  Engineering (In  Preparation.} 

Desaint,  A.     Three  Hundred  Shades  and  How  to  Mix  Them 8vo,  *io  oo 

De  Varona,  A.     Sewer  Gases.     (Science  Series  No.  55.)  i6mo,  o  50 

Devey,  R.  G.     Mill  and  Factory  Wiring.     (Installation  Manuals  Series.) 

I2H1O,  *I    OO 

Dibdin,  W.  J.     Public  Lighting  by  Gas  and  Electricity 8vo,  *8  oo 

Purification  of  Sewage  and  Water 8vo,  6  50 

Dichmann,  Carl.     Basic  Open-Hearth  Steel  Process i2mo,  *3  *> 

Dieterich,  K.     Analysis  of  Resins,  Balsams,  and  Gum  Resins 8vo,  *3  GO 

Dinger,  Lieut.  H.  C.     Care  and  Operation  of  Naval  Machinery .  . .  i2mo,  *2  oo 
Dixon,  D.  B.     Machinist's  and  Steam  Engineer's  Practical  Calculator. 

i6mo,  morocco,  i  25 

Doble,  W.  A.     Power  Plant  Construction  on  the  Pacific  Coast  (In  Press.) 
Dorr,  B.  F.    The  Surveyor's  Guide  and  Pocket  Table-book. 

i6mo,  morocco,  2  co 

Down,  P.  B.     Handy  Copper  Wire  Table i6mo,  *i  oo 

Draper,  C.  H.     Elementary  Text-book  of  Light,  Heat  and  Sound .  .  12210,  i  oo 

Heat  and  the  Principles  of  Thermo-dynamics i2mo,  *2  oo 

Duckwall,  E.  W.     Canning  and  Preserving  of  Food  Products 8vo,  *5  oo 

Dumesny,  P.,  and  Noyer,  J.     Wood  Products,  Distillates,  and  Extracts. 

8vo,  *4  50 
Duncan,  W.  G.,  and  Penman,  D.     The  Electrical  Equipment  of  Collieries. 

8vo,  *4  oo 


D  VAN  NOSTftAND  COMPANY'S  SHORT  TITLE  CATALOG        9 

Dunstan,  A.  E.,  and  Thole,  F.  B.  T.     Textbook  of  Practical  Chemistry. 

i2mo,  *i  40 

Duthie,  A.  L.    Decorative  Glass  Processes.     (Westminster  Series.)  .8vo,  *2  oo 

Dwight,  H.  B.     Transmission  Line  Formulas 8vo,  *2  oo 

Dyson,  S.  S.     Practical  Testing  of  Raw  Materials 8vo,  *5  oo 

Dyson,  S.  S.,  and  Clarkson,  S.  S.     Chemical  Works 8vo,  *y  50 

Eccles,  R.  G.,  and  Duckwall,  E.  W.    Food  Preservatives . . .  .8vo,  paper,  o  50 

Eddy,  H.  T.     Researches  in  Graphical  Statics 8vo,  i  50 

—  Maximum  Stresses  under  Concentrated  Loads     8vo,  i  50 

Edgcumbe,  K.     Industrial  Electrical  Measuring  Instruments 8vo,  *2  50 

Eissler,  M.     The  Metallurgy  of  Gold 8vo,  7  50 

-  The  Hydrometallurgy  of  Copper 8vo,  *4  50 

-  The  Metallurgy  of  Silver 8vo,  4  oo 

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—  Cyanide  Process  for  the  Extraction  of  Gold 8vo,  3  oo 

—  A  Handbook  on  Modern  Explosives 8vo,  5  oo 

Ekin,  T.  C.     Water  Pipe  and  Sewage  Discharge  Diagrams folio,  *3  oo 

Eliot,  C.  W.,  and  Storer,  F.  H.     Compendious  Manual  of  Qualitative 

Chemical  Analysis i2mo,  *i  25 

Elliot,  Major  G.  H.     European  Light-house  Systems 8vo,  5  oo 

Ennis,  Wm.  D.     Linseed  Oil  and  Other  Seed  Oils 8vo,  *4  oo 

—  Applied  Thermodynamics 8vo,  *4  50 

—  Flying  Machines  To-day i2mo,  *4  50 

-  Vapors  for  Heat  Engines i2mo,  *i  oo 

Erfurt,  J.     Dyeing  of  Paper  Pulp.     Trans,  by  J.  Hubner 8vo,  *7  50 

Ermen,  W.  F.  A.     Materials  Used  in  Sizing 8vo,  *2  oo 

Evans,  C.  A.     Macadamized  Roads (In  Press.) 

Ewing,  A.  J.     Magnetic  Induction  in  Iron 8vo,  *4  oo 

Fairie,  J.     Notes  on  Lead  Ores I2mo,  *i  oo 

—  Notes  on  Pottery  Clays i2mo,  *i  50 

Fairley,  W.,  and  Andre,  Geo.  J.     Ventilation  of  Coal  Mines.     (Science 

Series  No.  58.) i6mo,  o  50 

Fairweather,  W.  C.     Foreign  and  Colonial  Patent  Laws 8vo,  *3  oo 

Fanning,  J.  T.     Hydraulic  and  Water-supply  Engineering 8vo,  *5  oo 

Fauth,  P.     The  Moon  in  Modern  Astronomy.    Trans,  by  J.  McCabe. 

8vo,  *2  oo 

Fay,  I.  W.     The  Coal-tar  Colors 8vo,  *4  oo 

Fernbach,  R.  L.     Glue  and  Gelatine 8vo,  *3  oo 

—  Chemical  Aspects  of  Silk  Manufacture I2mo,  *i  oo 

Fischer,  E.     The  Preparation  of  Organic  Compounds.     Trans,  by  R.  V. 

Stanford i2mo,  *i  25 

Fish,  J.  C.  L.     Lettering  of  Working  Drawings Oblong  8vo,  i  oo 

Fisher,  H.  K.  C.,  and  Darby,  W.  C.     Submarine  Cable  Testing 8vo,  *3  50 

Fiske,  Lieut.  B.  A.     Electricity  in  Theory  and  Practice 8vo,  2  50 

Fleischmann,  W.     The  Book  of  the  Dairy.     Trans,  by  C.  M.  Aikman. 

8vo,  4  oo 
Fleming,  J.  A.     The  Alternate-current  Transformer.     Two  Volumes.  8vo. 

Vol.   L    The  Induction  of  Electric  Currents *5  oo 

Vol.  II.     The  Utilization  of  Induced  Currents *5  oo 


^0     D.  VAN  NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG 

Fleming,  J.  A.     Propagation  ef  Electric  Currents 8vo,  *3  oo 

Centenary  of  the  Electrical  Current 8vo,  *o  50 

Electric  Lamps  and  Electric  Lighting 8vo,  *3  oo 

Electrical  Laboratory  Notes  and  Forms 4to,  *5  oo 

A  Handbook  for  the  Electrical  Laboratory  and  Testing  Room.     Two 

Volumes 8vo,  each,  *s  oo 

Fleury,  P.     Preparation  and  Uses  of  White  Zinc  Paints 8vo,  *2  50 

Fleury,  H.     The  Calculus  Without  Limits  or  Infinitesimals.     Trans,  by 

C.  O.  Mailloux (In  Press.) 

Flynn,  P.  J.    Flow  of  Water.     (Science  Series  No.  84.) i2mo,  o  50 

—  Hydraulic  Tables.     (Science  Series  No.  66.) i6mo,  o  50 

Foley,  N.     British  and  American  Customary  and  Metric  Measures .  .  folio,  *3  oo 
Foster,  H.  A.     Electrical  Engineers'  Pocket-book.      (Seventh  Edition.) 

i2mo,  leather,  5  oo 

Engineering  Valuation  of  Public  Utilities  and  Factories 8vo,  *3  oo 

—  Handbook  of  Electrical  Cost  Data 8vo  (In  Press.) 

Foster,  Gen.  J.  G.     Submarine  Blasting  in  Boston  (Mass.)  Harbor    4to,  3  50 

Fowle,  F.  F.     Overhead  Transmission  Line  Crossings i2mo,  *i  50 

JThe  Solution  of  Alternating  Current  Problems 8vo  (In  Press.) 

Fox,  W.  G.     Transition  Curves.     (Science  Series  No.  no.) i6mo,  o  50 

Fox,  W.,  and  Thomas,  C.  W.     Practical  Course  in  Mechanical  Draw- 
ing   i2mo,  i  25 

Foye,  J.  C.     Chemical  Problems.     (Science  Series  No.  69.) i6mo,  o  50 

—  Handbook  of  Mineralogy.     (Science  Series  No.  86.) i6mo,  o  50 

Francis,  J.  B.     Lowell  Hydraulic  Experiments 4to,  15  oo 

Freudemacher,   P.   W.     Electrical   Mining  Installations.     (Installation 

Manuals  Series.) i2mo,  *i  oo 

Frith,  J.     Alternating  Current  Design 8vo,  *2  oo 

Fritsch,  J.     Manufacture  of  Chemical  Manures.     Trans,  by  D.  Grant. 

8vo,  *4  oo 

Frye,  A.  I.     Civil  Engineers'  Pocket-book i2mo,  leather,  *s  oo 

Fuller,  G.  W.     Investigations  into  the  Purification  of  the  Ohio  River. 

4to,  *io  oo 

Furnell,  J.    Paints,  Colors,  Oils,  and  Varnishes 8vo.  *i  oo 

Gairdner,  J.  W.  I.     Earthwork 8vo  (In  Press.) 

Gant,  L.  W.    Elements  of  Electric  Traction 8vo,  *2  50 

Garcia,  A.  J.  R.  V.     Spanish-English  Railway  Terms 8vo,  *4  50 

Garforth,  W.  E.    Rules  for  Recovering  Coal  Mines  after  Explosions  and 

Fires i2mo,  leather,  i  50 

Gaudard,  J.    Foundations.     (Science  Series  No.  34.) i6mo,  o  50 

Gear,  H.  B.,  and  Williams,  P.  F.    Electric  Central  Station  Distribution 

Systems 8vo,  *3  oo 

Geerligs,  H.  C.  P.     Cane  Sugar  and  Its  Manufacture 8vo,  *5  oo 

—  World's  Cane  Sugar  Industry 8vo,  *5  oo 

Geikie,  J.     Structural  and  Field  Geology 8vo,  *4  oo 

Gerber,  N.   Analysis  of  Milk, Condensed  Milk, and  Infants' Milk- Food.    8vo,  i  25 
Gerhard,  W.  P.     Sanitation,  Watersupply  and  Sewage  Disposal  of  Country 

Houses I2H1O,  *2    OO 

Gas  Lighting.     (Science  Series  No.  in.) i6mo,  o  50 

Household  Wastes.     (Science  Series  No.  97.) i6mo,  o  50 

House  Drainage.     (Science  Series  No.  63.) i6mo,  o  50 


D.  VAN    NOSTRAND   COMPANY'S   SHORT   TITLE  CATALOG      11 

Gerhard,  W  P-     Sanitary  Drainage  of  Buildings.    (Science  Series  No.  93.) 

i6mo,  o  50 

Gerhardi,  C.  W.  H.     Electricity  Meters 8vo,  *4  oo 

Geschwind,    L.     Manufacture   of   Alum   and  Sulphates.     Trans,   by   C. 

Salter 8vo,  *s  oo 

Gibbs,  W.  E.     Lighting  by  Acetylene i2mo,  *i  50 

—  Physics  of  Solids  and  Fluids.     (Carnegie  Technical  School's  Text- 

books.)   *i  50 

Gibson,  A.  H.     Hydraulics  and  Its  Application 8vo,  *s  oo 

-  Water  Hammer  in  Hydraulic  Pipe  Lines 12 mo,  *2  oo 

Gilbreth,  F.  B.     Motion  Study iimo,  *2  oo 

—  Primer  of  Scientific  Management i2mo,  *i  oo 

Gillmore,  Gen.  Q.  A.     Limes,  Hydraulic  Cements  and  Mortars 8vo,  4  oo 

Roads,  Streets,  and  Pavements i2mo,  2  oo 

Golding,  H.  A.     The  Theta-Phi  Diagram i2mo,  *i  25 

Goldschmidt,  R.     Alternating  Current  Commutator  Motor 8vo,  *3  oo 

Goodchild,  W      Precious  Stones.     (Westminster  Series.) 8vo,  *2  oo 

Goodeve,  T.  M.     Textbook  on  the  Steam-engine i2mo,  2  oo 

Gore,  G.     Electrolytic  Separation  of  Metals 8vo,  *3  50 

Gould,  E.  S.     Arithmetic  of  the  Steam-engine I2mo,  i  oo 

—  Calculus.     (Science  Series  No.  112.) 16010,  o  50 

High  Masonry  Dams.     (Science  Series  No.  22.) i6mo,  o  50 

Practical  Hydrostatics  and  Hydrostatic  Formulas.     (Science  Series 

No.  1 17.) i6mo,  o  50 

Grant,  J.     Brewing  and  Distilling.     (Westminster  Series.)  8vo  (In  Press.) 

Gratacap,  L.  P.    A  Popular  Guide  to  Minerals 8vo,  *3  oo 

Gray,  J.     Electrical  Influence  Machines i2mo,  2  oo 

—  Marine  Boiler  Design i2mo,  *i  25 

Greenhiil,  G.     Dynamics  of  Mechanical  Flight 8vo,  *2  50 

Greenwood,  E.     Classified  Guide  to  Technical  and  Commercial  Books.  8vo,  *3  oo 

Gregorius,  R.     Mineral  Waxes.     Trans,  by  C.  Salter i2mo,  *3  oo 

Griffiths,  A.  B.     A  Treatise  on  Manures I2mo,  3  oo 

—  Dental  Metallurgy 8vo,  *3  50 

Gross,  E.     Hops 8vo,  *4  50 

Grossman,  J.     Ammonia  and  Its  Compounds i2mo,  *i  25 

Groth,  L.  A.    Welding  and  Cutting  Metals  by  Gases  or  Electricity.  .8vo,  *2  oo 

Grover,  F.     Modern  Gas  and  Oil  Engines 8vo,  *2  oo 

Gruner,  A.     Power-loom  Weaving 8vo,  *3  oo 

Guldner,  Hugo.     Internal  Combustion  Engines.     Trans,  by  H.  Diederichs. 

4to,  *io  oo 

Gunther,  C.  O.     Integration. I2mo,  *i  25 

Gurden,  R.  L.     Traverse  Tables folio,  half  morocco,  *7  50 

Guy,  A.  E.     Experiments  on  the  Flexure  of  Beams 8vo,  *i  25 

Haeder,    H.      Handbook   on    the    Steam-engine.      Trans,  by  H.  H.  P. 

Powles ." i2mo,  3  oo 

Hainbach,  R.     Pottery  Decoration.     Trans,  by  C.  Slater i2mo,  *3  oo 

Haenig,  A.    Emery  and  Emery  Industry 8vo,  *2  50 

Hale,  W.  J,     Calculations  of  General  Chemistry i2mo,  *i  oo 

Hall,  C.  H.     Chemistry  of  Paints  and  Paint  Vehicles i2mo,  *2  oo 

Hall,  R.  H.     Governors  and  Governing  Mechanism i2mo,  *2  oo 


00 
00 

50 
50 

50 


12     D.   VAN    NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG 

Hall,  W.  S.     Elements  of  the  Differential  and  Integral  Calculus 8vo,  *2  25 

Descriptive  Geometry 8vo  volume  and  a  4to  atlas,  *3  50 

Haller,  G.  F.,  and  Cunningham,  E.  T.     The  Tesla  Coil i2mo,  *i  25 

Halsey,  F.  A.     Slide  Valve  Gears i2mo,  i  50 

The  Use  of  the  Slide  Rule.     (Science  Series  No.  114.) i6mo,  o  50 

Worm  and  Spiral  Gearing.     (Science  Series  No.  116.) i6mo,  o  50 

Hamilton,  W.  G.     Useful  Information  for  Railway  Men i6mo, 

Hammer,  W.  J.     Radium  and  Other  Radio-active  Substances ..;....  8 vo, 

Hancock,  H.     Textbook  of  Mechanics  and  Hydrostatics 8vo, 

Hardy,  E.     Elementary  Principles  of  Graphic  Statics i2mo, 

Harrison,  W.  B.     The  Mechanics'  Tool-book i2mo, 

Hart,  J.  W.     External  Plumbing  Work 8vo,  *3  oo 

Hints  to  Plumbers  on  Joint  Wiping 8vo,  *3  oo 

Principles  of  Hot  Water  Supply 8vo,  *3  oo 

Sanitary  Plumbing  and  Drainage 8vo,  *3  oo 

Haskins,  C.  H.     The  Galvanometer  and  Its  Uses i6mo,  i  50 

Hatt,  J.  A.  H.     The  Colorist square  i2mo,  *i  50 

Hausbrand,  E.     Drying  by  Means  of  Air  and  Steam.     Trans,  by  A.  C. 

Wright i2mo,  *2  oo 

Evaporating,  Condensing  and  Cooling  Apparatus.     Trans,  by  A.  C. 

Wright 8vo,  *s  oo 

Hausner,  A.     Manufacture  of  Preserved  Foods  and  Sweetmeats.     Trans. 

by  A.  Morris  and  H.  Robson 8vo,  *3  oo 

Hawke,  W.  H.     Premier  Cipher  Telegraphic  Code 4to,  *5  oo 

100,000  Words  Supplement  to  the  Premier  Code 4to,  *5  oa 

Hawkesworth,  J.     Graphical  Handbook  for  Reinforced  Concrete  Design. 

4to,  *2  50 

Hay,  A.     Alternating  Currents 8vo,  *2  50 

— —  Electrical  Distributing  Networks  and  Distributing  Lines 8vo,  *3  50 

Continuous  Current  Engineering 8vo,  *2  50 

Hayes,  H.  V.    Public  Utilities,  Their  Cost  New  and  Depreciation. .  .8vo,  *2  oo 

Heap,  Major  D.  P.     Electrical  Appliances 8vo,  2  oo 

Heather,  H.  J.  S.     Electrical  Engineering 8vo,  *3  50 

Heaviside,  O.     Electromagnetic  Theory.      Vols.  I  and  II. ..  .8vo,  each,  *5  oo 

Vol.  Ill 8vo,  *7  50 

Heck,  R.  C.  H.    The  Steam  Engine  and  Turbine 8vo,  *5  oo 

Steam-Engine  and  Other  Steam  Motors.    Two  Volumes. 

Vol.   I.     Thermodynamics  and  the  Mechanics 8vo,  *3  50 

Vol.  II.     Form,  Construction,  and  Working 8vo,  *5  oo 

Notes  on  Elementary  Kinematics 8vo,  boards,  *i  oo 

Graphics  of  Machine  Forces 8vo,  boards,  *i  oo 

Hedges,  K.     Modern  Lightning  Conductors 8vo,  3  oo 

Heermann,  P.     Dyers' Materials.     Trans,  by  A.  C.  Wright i2mo,  *2  50 

Hellot,  Macquer  and  D'Apligny.   Art  of  Dyeing  Wool,  Silk  and  Cotton.  8vo,  *2  oo 

Henrici,  0.     Skeleton  Structures 8vo,  i  50 

Hering,  D.  W.    Essentials  of  Physics  for  College  StUdents 8vo,  *i  75 

Hering-Shaw,  A.     Domestic  Sanitation  and  Plumbing.     Two  Vols. .  .  8vo,  *5  oo 

Hering-Shaw,  A.     Elementary  Science 8vo,  *2  oo 

Herrmann,  G.     The  Graphical  Statics  of  Mechanism.     Trans,  by  A.  P. 

Smith i2mo,  2  oo 

Herzfeld,  J.     Testing  of  Yarns  and  Textile  Fabrics 8vo,  *3  50 


D.   VAN    NOSTRAND   COMPANY'S  SHORT  TITLE  CATALOG      13 

Hildebrandt,  A.     Airships,  Past  and  Present 8vo,  *3  50 

flildenbrand,  B.  W.     Cable-Making.     (Science  Series  No.  32.) i6mo,  o  50 

Hilditch,  T.  P.     A  Concise  History  of  Chemistry 12010,  *i  25 

Hill,  J.  W.     The  Purification  of  Public  Water  Supplies.     New  Edition.  . 

(In  Press.} 

—  Interpretation  of  Water  Analysis (In  Press.) 

Hiroi,  I.     Plate  Girder  Construction.     (Science  Series  No.  95.). ....  i6mo,  o  50 

-  Statically-Indeterminate  Stresses i2mo,  *2  oo 

Hirshfeld,  C.  F.     Engineering  Thermodynamics.     (Science  Series  No.  45.) 

i6mo,  o  50 

Hobart,  H.  M.     Heavy  Electrical  Engineering 8vo,  *4  50 

Design  of  Static  Transformers i2mo,  *2  oo 

Electricity 8vo,  *2  oo 

—  Electric  Trains 8vo,  *2  50 

Hobart,  H.  M.    Electric  Propulsion  of  Ships 8vo,  *2  oo 

Hobart,  J.  F.     Hard  Soldering,  Soft  Soldering  and  Brazing izmo,  *i  oo 

Hobbs,  W.  R.  P.     The  Arithmetic  of  Electrical  Measurements i2mo,  o  50 

Hoff,  J.  N.     Paint  and  Varnish  Facts  and  Formulas I2ino,  *i  50 

Hole,  W.     The  Distribution  of  Gas 8vo,  *7  50 

Holley,  A.  L.     Railway  Practice folio,  12  oo 

Holmes,  A.  B.     The  Electric  Light  Popularly  Explained  ....  12010,  paper,  o  50 

Hopkins,  N.  M.     Experimental  Electrochemistry 8vo,  *3  oo 

—  Model  Engines  and  Small  Boats 12010,  i  25 

Hopkinson,  J.     Shoolbred,  J.  N.,  and  Day,  R.  E.     Dynamic  Electricity. 

(Science  Series  No.  71.) i6mo,  o  50 

Homer,  J.     Engineers'  Turning .  8vo,  *3  50 

—  Metal  Turning ' i2mo,  i  50 

-  Toothed  Gearing i2mo,  2  25 

Houghton,  C.  E.     The  Elements  of  Mechanics  of  Materials i2mo,  *2  oo 

Houllevigue,  L.    The  Evolution  of  the  Sciences 8vo,  *2  oo 

Houstoun,  R.  A.     Studies  in  Light  Production i2mo,  *2  oo 

Howe,  G.     Mathematics  for  the  Practical  Man i2mo,  *i  25 

Howorth,  J.     Repairing  and  Riveting  Glass,  China  and  Earthenware. 

8vo,  paper,  *o  50 

Hubbard,  E.     The  Utilization  of  Wood- waste 8vo,  *2  50 

Hu'bner,  J.    Bleaching  and  Dyeing  of  Vegetable  and  Fibrous  Materials 

(Outlines  of  Industrial  Chemistry) 8vo,  *5  oo 

Hudson,  O.  F.    Iron  and  Steel.     (Outlines  of  Industrial  Chemistry.) .  8vo,  *2  oo 

Humper,  W.     Calculation  of  Strains  in  Girders i2mo,  2  50 

Humphreys,  A.  C.    The  Business  Features  of  Engineering  Practice .  8vo,  *i  25 

Hunter,  A.    Bridge  Work 8vo,  (In  Press.) 

Hurst,  G.  H.     Handbook  of  the  Theory  of  Color 8vo,  *2  5® 

—  Dictionary  of  Chemicals  and  Raw  Products 8vo,  *3  oo 

—  Lubricating  Oils,  Fats  and  Greases .  .  .  .' 8vo,  *4  oo 

—  Soaps 8vo,  <*5  oo 

Hurst,  G.  H.     Textile  Soaps  and  Oils  . 8vo,  *2  50 

Hurst,  H.  E.,  and  Lattey,  R.  T.     Text-book  of  Physics  .  .  . 8vo,  *3  oo 

—  Also  published  in  three  parts. 

Part     I.     Dynamics  and  Heat *i  25 

Part   II.     Sound  and  Light *i  25 

Part  III.     Magnetism  and  Electricity *i  50 


14     D.  VAN  N3STRAND  COMPANY'S  SHORT  TITLE  CATALOG 

Hutchinson,  R.  W.,  Jr.     Long  Distance  Electric  Power  Transmission. 

i2mo,  *3  oo 

Hutchinson,  R.  W.,  Jr.,  and  Dilseng,  M.  C.     Electricity  in  Mining .  .  i2mo, 

(In  Press.) 
Hutchinson,  W.  B.     Patents  and  How  to  Make  Money  Out  of  Them. 

i2mo,  i  25 

Hutton,  W.  S.     Steam-boiler  Construction 8vo,  6  oo 

—  Practical  Engineer's  Handbook 8vo,  7  oo 

-  The  Works'  Manager's  Handbook 8vo,  6  oo 

Hyde,  E.  W.     Skew  Arches.     (Science  Series  No.  15.) i6mo,  o  50 

Hyde,  F.  S.     Solvents,  Oils,  Gums,  Waxes 12010,  *2  oo 

Induction  Coils.     (Science  Series  No.  53.) i6mo,  o  50 

Ingle,  H.     Manual  of  Agricultural  Chemistry 8vo,  *3  oo 

Inness,  C.  H.    Problems  in  Machine  Design i2mo,  *2  oo 

Air  Compressors  and  Blowing  Engines i2mo,  *2  oo 

Centrifugal  Pumps i2mo,  *2  oo 

The  Fan i2mo,  *2  oo 

Isherwood,  B.  F.    Engineering  Precedents  for  Steam  Machinery . . .  8vo,  2  50 

Ivatts,  E.  B.    Railway  Management  at  Stations 8vo,  *2  50 

Jacob,  A.,  and  Gould,  E.  S.     On  the  Designing  and  Construction  of 

Storage  Reservoirs.     (Science  Series  No.  6) i6mo,  o  50 

Jamieson,  A.     Text  Book  on  Steam  and  Steam  Engines 8vo,  3  oo 

Elementary  Manual  on  Steam  and  the  Steam  Engine i2mo,  i  50 

Jannettaz,  E.     Guide  to  the  Determination  of  Rocks.     Trans,  by  G.  W. 

Plympton ." i2mo,  i  50 

Jehl,  F.     Manufacture  of  Carbons 8vo,  *4  oo 

Jennings,  A.  S.     Comm  ercial  Paints  and  Painting.   (Westminster  Series. ) 

Svo  (In  Press.) 

Jennison,  F.  H.    The  Manufacture  of  Lake  Pigments Svo,  *3  oo 

Jepson,  G.     Cams  and  the  Principles  of  their  Construction Svo,  *i  50 

—  Mechanical  Drawing Svo  (In  Preparation.) 

Jockin,  W.    Arithmetic  of  the  Gold  and  Silversmith i2mo,  *i  oo 

Johnson,  G.  L.    Photographic  Optics  and  Color  Photography Svo,  *3  oo 

Johnson,  J.  H.    Arc  Lamps  and  Accessory  Apparatus.     (Installation 

Manuals  Series.) i2mo,  *o  75 

Johnson,  T.  M.     Ship  Wiring  and  Fitting.     (Installation  Manuals  Series.) 

i2mo,  *o  75 

Johnson,  W.  H.    The  Cultivation  and  Preparation  of  Para  Rubber .  .Svo,  *3  oo 

Johnson,  W.  McA.     The  Metallurgy  of  Nickel (In  Preparation.) 

Johnston,  J.  F.  W.,  and  Cameron,  C.    Elements  of  Agricultural  Chemistry 

and  Geology i2mo,  2  60 

Joly,  ].    Radioactivity  and  Geology i2mo,  *3  oo 

Jones,  H.  C.    Electrical  Nature  of  Matter  and  Radioactivity i2mo,  *2  oo 

—  New  Era  in  Chemistry i2mo,  *2  oo 

Jones,  M.  W.     Testing  Raw  Materials  Used  in  Paint i2mo,  *2  oo 

Jones,  L.,  and  Scard,  F.  I.     Manufacture  of  Cane  Sugar Svo,  *$  oo 

Jordan,  L.  C.     Practical  Railway  Spiral i2mo,  leather,  *i  50 

Joynson,  F.  H.    Designing  and  Construction  of  Machine  Gearing  . .  Svo,  2  oo 

Jiiptner,  H.  F.  V.     Siderology :  The  Science  of  Iron Svo,  *5  oo 


D.  VAN  NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG     15 

Kansas  City  Bridge 4to,  6  oo 

Kapp,  G.     Alternate  Current  Machinery.     (Science  Series  No.  96.). i6mo,  o  50 

—  Electric  Transmission  of  Energy i2mo,  3  50 

Keim,  A.  W.     Prevention  of  Dampness  in  Buildings 8vo,  *2  oo 

Keller,  S.  S.     Mathematics  for  Engineering  Students.     1 2mo,  half  leather. 

Algebra  and  Trigonometry,  with  a  Chapter  on  Vectors *i  75 

Special  Algebra  Edition *i .  oo 

Plane  and  Solid  Geometry *i .  25 

Analytical  Geometry  and  Calculus *2  oo 

Kelsey,  W.  R.     Continuous-current  Dynamos  and  Motors 8vo,  *2  50 

Kemble,  W.  T.,  and  Underbill,  C.  R.     The  Periodic  Law  and  the  Hydrogen 

Spectrum 8vo,  paper,  *o  50 

Kemp,  J.  F.     Handbook  of  Rocks .8vo,  *i  50 

Kendall,  E.     Twelve  Figure  Cipher  Code 4to,  *i2  50 

Kennedy,  A.  B.  W.,  and  Thurston,  R.  H.     Kinematics  of  Machinery. 

(Science  Series  No.  54.) i6mo,  o  50 

Kennedy,  A.  B.  W.,  Unwin,  W.  C.,  and  Idell,  F.  E.     Compressed  Air. 

(Science  Series  No.  106.) i6mo,  o  50 

Kennedy,  R.     Modern  Engines  and  Power  Generators.  Six  Volumes.  4to,  15  oo 

Single  Volumes each,  3  oo 

—  Electrical  Installations.     Five  Volumes , 4to,  15  oo 

Single  Volumes , each,  3  50 

—  Flying  Machines;  Practice  and  Design i2mo,  *2  oo 

—  Principles  of  Aeroplane  Construction 8vo,  *i  50 

Kennelly,  A.  E.     Electro-dynamic  Machinery 8vo,  i  50 

Kent,  W.     Strength  of  Materials.     (Science  Series  No.  41.) i6mo,  o  50 

Kershaw,  J.  B.  C.     Fuel,  Water  and  Gas  Analysis 8vo,  *2  50 

—  Electrometallurgy.     (Westminster  Series.) 8vo,  *2  oo 

-  The  Electric  Furnace  in  Iron  and  Steel  Production iimo,  *i  50 

Kinzbrunner,  C.     Alternate  Current  Windings 8vo,  *i  50 

—  Continuous  Current  Armatures 8vo,  *i  50 

-  Testing  of  Alternating  Current  Machines 8vo,  *2  oo 

Kirkaldy,  W.  G.     David  Kirkaldy's  System  of  Mechanical  Testing.  .4to,  10  oo 

Kirkbride,  J.     Engraving  for  Illustration 8vo,  *i  50 

Kirkwood,  J.  P.     Filtration  of  River  Waters 4to,  7  50 

Kirschke,  A.     Gas  and  Oil  Engines i2mo,  *i  25 

Klein,  J.  F.     Design  of  a  High-speed  Steam-engine 8vo,  *$  oo 

—  Physical  Significance  of  Entropy 8vo,  *i  50 

Kleinhans,  F.  B.     Boiler  Construction 8vo,  3  oo 

Knight,  R.-Adm.  A.  M.     Modern  Seamanship 8vo,  *7  50 

Half  morocco *9  oo 

Knox,  J.     Physico-Chemical  Calculations i2mo,  *i  oo 

Knox,  W.  F.     Logarithm  Tables (In  Preparation.) 

Knotty  C.  G.,  and  Mackay,  J.  S.     Practical  Mathematics 8vo,  2  oo 

Koester,  F.     Steam-Electric  Power  Plants 4to,  *5  oo 

—  Hydroelectric  Developments  and  Engineering 4to,  *5  oo 

Koller,  T.     The  Utilization  of  Waste  Products 8vo,*3  50 

Cosmetics 8vo,  *2  50 

Kremann,  R.     Technical  Processes  and  Manufacturing  Methods.     Trans. 

by  H.  E.  Potts 8vo, 

00 


16     D.  VAN  NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG 

Lallier,  E.  V.     Elementary  Manual  of  the  Steam  Engine i2mo,  *2  oo 

Lambert,  T.     Lead  and  Its  Compounds 8vo,  *3  50 

—  Bone  Products  and  Manures 8vo,  *3  oo 

Lamborn,  L.  L.     Cottonseed  Products 8vo,  *3  oo 

—  Modern  Soaps,  Candles,  and  Glycerin 8vo,  *7  50 

Lamprecht,  R.     Recovery  Work  After  Pit  Fires.    Trans,  by  C.  Salter .  8vo,  *4  oo 
Lanchester,  F.  W.     Aerial  Flight.     Two  Volumes.     8vo. 

Vol.  I.     Aerodynamics *6  oo 

—  Aerial  Flight.     Vol.  II.     Aeroionetics *6 . oo 

Larner,  E.  T.     Principles  of  Alternating  Currents i2mo.     *i  25 

Larrabee,  C.  S.     Cipher  and  Secret  Letter  and  Telegraphic  Code.  i6mo,      o  60 

La  Rue,  B.  F.     Swing  Bridges.     (Science  Series  No.  107.) i6mo,      o  50 

Lassar-Cohn.  Dr.     Modern  Scientific   Chemistry.     Trans,  by  M.  M. 

Pattison  Muir i2mo,     *2  oc 

Latimer,  L.  H.,  Field,  C.  J.,  and  Howell,  J.  W.     Incandescent  Electric 

Lighting.     (Science  Series  No.  57.)     i6mo,      o  50 

Latta,  M.  N.     Handbook  of  American  Gas-Engineering  Practice  . . .  8vo,     *4  50 

American  Producer  Gas  Practice 4to,     V6  oo 

Leask,  A.  R.    Breakdowns  at  Sea i2mo,      2  oo 

Refrigerating  Machinery i2mo,      2  oo 

Lecky,  S.  T.  S.     "  Wrinkles  "  in  Practical  Navigation 8vo,     *8  oo 

Le  Doux,  M.     Ice-Making  Machines.     (Science  Series  No.  46.) . .  i6mo,      o  50 

Leeds,  C.  C.     Mechanical  Drawing  for  Trade  Schools oblong   4to, 

High  School  Edition *i  25 

Machinery  Trades  Edition *2 .  oo 

Lefevre,  L.    Architectural  Pottery.     Trans,  by  H.  K.  Bird  and  W.  M. 

Binns 4to,     *7  50 

Lehner,  S.     Ink  Manufacture.     Trans,  by  A.  Morris  and  H.  Robson .  8vo,     *2  50 

Lemstrom,  S.    Electricity  in  Agruiclture  and  Horticulture 8vo,     *i  50 

Le  Van,  W.  B.    Steam-Engine  Indicator.    (Science  Series  No.  78.)i6mo,      o  50 
Lewes,  V.  B.     Liquid  and  Gaseous  Fuels.     (Westminster  Series.).  .8vo,     *2  oo 

Carbonization  of  Coal 8vo,     *3  oo 

Lewis,  L.  P.    Railway  Signal  Engineering 8vo,     *3  50 

Lieber,  B.  F.     Lieber's  Standard  Telegraphic  Code 8vo,  *io  oo 

—  Code.     German  Edition 8vo,  *io  oo 

Spanish  Edition 8vo,  *io  oo 

French  Edition 8vo,  *io  oo 

—  Terminal  Index 8vo,     *2  50 

Lieber's  Appendix folio,  *i$  oo 

—  Handy  Tables 4to,  *2  50 

Bankers  and  Stockbrokers'  Code  and  Merchants  and  Shippers' 

Blank  Tables 8vo,  *i$  oo 

—  100,000,000  Combination  Code 8vo,  *io  oo 

—  Engineering  Code 8vo,  *i2  50 

Livermore,  V.  P.,  and  Williams,  J.     How  to  Become  a  Competent  Motor- 
man  i2mo,  *i  oo 

Liversedge,  A.  J.     Commercial  Engineering 8vo,  *3  oo 

Livingstone,  R.     Design  and  Construction  of  Commutators 8vo,  *2  25 

Lobben,  P.     Machinists'  and  Draftsmen's  Handbook 8vo,  2  50 

Locke,  A.  G.  and  C.  G.     Manufacture  of  Sulphuric  Acid 8vo,  10  oo 

Lockwood,  T.  D.    Electricity,  Magnetism,  and  Electro-telegraph ....  8vo,  2  50 


D.  VAN  NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG      17 

Lockwood,  T.  D.    Electrical  Measurement  and  the  Galvanometer. 

i2mo,  o  75 

Lodge,  O.  J.  Elementary  Mechanics i2mo,  i  50 

—  Signalling  Across  Space  without  Wires 8vo,  *2  oo 

Loewenstein,  L.  C.,  and  Crissey,  C.  P.     Centrifugal  Pumps *4  50 

Lord,  R.  T.     Decorative  and  Fancy  Fabrics 8vo,  *3  50 

Loring,  A.  E.     A  Handbook  of  the  Electromagnetic  Telegraph  ....  i6mo,  o  50 

-  Handbook.     (Science  Series  No.  39.) i6mo,  o  50 

Low,  D.  A.     Applied  Mechanics  (Elementary) i6mo,  o  80 

Lubschez,  B.  J.     Perspective I2mo,  *i  50 

Lucke,  C.  E.     Gas  Engine  Design 8vo,  *3  oo 

Power  Plants:   Design,  Efficiency,  and  Power  Costs.     2  vols. 

(In  Preparation.} 
Lunge,  G.     Coal-tar  and  Ammonia.     Two  Volumes 8vo,  *i$  oo 

—  Manufacture  of  Sulphuric  Acid  and  Alkali.     Four  Volumes ....  8vo, 

Vol.     I.     Sulphuric  Acid.     In  three  parts *i8  oo 

Vol.  II.     Salt  Cake,  Hydrochloric  Acid  and  Leblanc  Soda.    In  two 

parts *i$ .  oo 

Vol.  III.     Ammonia  Soda *io  oo 

Vol.  IV.     Electrolytic  Methods (In  Press.) 

-  Technical  Chemists'  Handbook I2mo,  leather,     *3  50 

-  Technical  Methods  of  Chemical  Analysis.     Trans  by  C.  A.  Keane. 

in  collaboration  with  the  corps  of  specialists. 

Vol.     I.     In  two  parts 8vo,  *i$  oo 

Vol.    II.     In  two  parts 8vo,   *i8  oo 

Vol.  in (In  Preparation.) 

Lupton,  A.,  Parr,  G.  D.  A.,  and  Perkin,  H.    Electricity  as  Applied  to 

Mining 8vo,     *4  50 

Luquer,  L.  M.     Minerals  in  Rock  Sections 8vo,     *i  50 

Macewen,  H.  A.     Food  Inspection 8vo,  *2  50 

Mackenzie,  N.  F.     Notes  on  Irrigation  Works 8vo,  *2  50 

Mackie,  J.     How  to  Make  a  Woolen  Mill  Pay 8vo,  *2  oo 

Mackrow,  C.     Naval  Architect's  and  Shipbuilder's  Pocket-book. 

i6mo,  leather,  5  oo 

Maguire,  Wm.  R.     Domestic  Sanitary  Drainage  and  Plumbing  .  .  .  .8vo,  4  oo 
Mallet,  A.     Compound  Engines.     Trans,  by  R.  R.  Buel.     (Science  Series 

No.  10.) i6mo, 

Mansfield,  A.  N.     Electro-magnets.     (Science  Series  No.  64.)  . .  .  i6mo,  o  50 

Marks,  E.  C.  R.     Construction  of  Cranes  and  Lifting  Machinery  .i2mo,  *i  50 

—  Construction  and  Working  of  Pumps i2mo,  *i  50 

—  Manufacture  of  Iron  and  Steel  Tubes i2mo,  *2  05 

—  Mechanical  Engineering  Materials i2mo,  *i  o  J 

Marks,  G.  C.     Hydraulic  Power  Engineering 8vo,  353 

—  Inventions,  Patents  and  Designs i2mo,  *i  oo 

Mario w,  T.  G.     Drying  Machinery  and  Practice 8vo,  *5  oo 

Marsh,  C.  F.     Concise  Treatise  on  Reinforced  Concrete  8vo,  *2  50 

—  Reinforced  Concrete  Compression  Member  Diagram.     Mounted  on 

Cloth  Boards *i .  50 

Marsh,  C.  F.,  and  Dunn,  W.     Manual  of  Reinforced  Concrete  and  Con- 
crete Block  Construction i6mo,  morocco,     *2  50 


18     D.  VAN  NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG 

Marshall,  W.  J.,  and  Sankey,  H.  R.     Gas  Engines.     (Westminster  Series.) 

8vo,  *2  oo 

Martin,  G.     Triumphs  and  Wonders  of  Modern  Chemistry 8vo,  *2  oo 

Martin,  N.    Properties  and  Design  of  Reinforced  Concrete i2mo,  *2  50 

Massie,  W.  W.,  and  Underbill,  C.  R.     Wireless  Telegraphy  and  Telephony. 

i2mo,  *i  oo 
Matheson,D.   Australian  Saw-Miller's  Log  and  Timber  Ready  Reckoner. 

i2mo,  leather,  i  50 

Mathot,  R.  E.     Internal  Combustion  Engines 8vo,  *6  oo 

Maurice,  W.     Electric  Blasting  Apparatus  and  Explosives .  .8vo,  *3  50 

—  Shot  Firer's  Guide 8vo,  *i  50 

Maxwell,  J.  C.     Matter  and   Motion.     (Science  Series  No.  36.). 

i6mo,  o  sc 

Maxwell,  W.  H.,  and  Brown,  J.  T.    Encyclopedia  of  Muncipal  and  Sani- 
tary Engineering 4to,  *io  oo 

Mayer,  A.  M.     Lecture  Notes  on  Physics 8vo,  2  oo 

McCullough,  R.  S.     Mechanical  Theory  of  Heat 8vo,  3  50 

Mclntosh,  J.  G.     Technology  of  Sugar 8vo,  *4  50 

Industrial  Alcohol 8vo,  *3  oo 

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8vo. 

Vol.     I.     Oil  Crushing,  Refining  and  Boiling *3  So 

Vol.   II.    Varnish  Materials  and  Oil  Varnish  Making *4  oo 

Vol.  III.     Spirit  Varnishes  and  Materials *4  50 

McKnight,  J.  D.,  and  Brown,  A.  W.     Marine  Multitubular  Boilers *i  50 

McMaster,  J.  B.    Bridge  and  Tunnel  Centres.     (Science  Series  No.  20.) 

i6mo,  o  50 

McMechen,  F.  L.     Tests  for  Ores,  Minerals  and  Metals i2mo,  *i  oo 

McNeill,  B.     McNeill's  Code 8vo,  *6  oo 

McPherson,  J.  A.     Water- works  Distribution 8vo,  2  50 

Melick,  C.  W.     Dairy  Laboratory  Guide i2mo,  *i  25 

Merck,  E.     Chemical  Reagents ;  Their  Purity  and  Tests 8vo,  *i  50 

Merritt,  Wm.  H.    Field  Testing  for  Gold  and  Silver i6mo,  leather,  i  50 

Messer,  W.  A.     Railway  Permanent  Way 8vo  (In  Press.) 

Meyer,  J.  G.  A.,  and  Pecker,  C.  G.     Mechanical  Drawing  and  Machine 

Design 4to,  5  oo 

Michell,  S.     Mine  Drainage 8vo,  10  oo 

Mierzinski,  S.     Waterproofing  of  Fabrics.     Trans,  by  A.  Morris  and  H. 

Robson 8vo,  *2  50 

Miller,  G.  A.    Determinants.     (Science  Series  No  105.) i6mo, 

Milroy,  M.  E.  W.     Home  Lace-making i2mo,  *i  oo 

Minifie,  W.     Mechanical  Drawing 8vo,  *4  oo 

Mitchell,  C.  A.     Mineral  and  Aerated  Waters 8vo,  *3  oo 

Mitchell,  C.  A.,  and  Prideaux,  R.  M.    Fibres  Used  in  Textile  and  Allied 

Industries .' 8vo,  *3  oo 

Mitchell,  C.  F.,  and  G.  A.    Building  Construction  and  Drawing.     i2mo. 

Elementary  Course *i  50 

Advanced  Course *2  50 

Monckton,  C.  C.  F.     Radiotelegraphy.     (Westminster  Series.) 8vo,  *2  oo 

Monteverde,  R.  D.     Vest  Pocket  Glossary  of  English- Spanish,  Spanish- 
English  Technical  Terms 64mo,  leather,  *i  oo 


D.  VAN  NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG      19 

Moore,  E.  C.  S.     New  Tables  for  the  Complete  Solution  of  Ganguillet  and 

Kutter's  Formula 8vo,  *s  oo 

Morecroft,  J.  H.,  and  Hehre,  F.  W.     Short  Course  in  Electrical  Testing. 

8vo,  *i  50 
Moreing,  C.  A.,  and  Neal,  T.     New  General  and  Mining  Telegraph  Code. 

8vo,  *s  oo 

Morgan,  A.  P.     Wireless  Telegraph  Apparatus  for  Amateurs i2mo,  *i  50 

Moses,  A.  J.     The  Characters  of  Crystals 8vo,  *2  oo 

Moses,  A.  J.,  and  Parsons,  C.  L.    Elements  of  Mineralogy    8vo,  *2  50 

Moss,  S.A.  Elements  of  Gas  Engine  Design.  (Science  Series  No.  121.)  i6mo,     o  50 
-  The  Lay-out  of  Corliss  Valve  Gears.     (Science  Series  No.  1 19.)  i6mo,     o  50 

Mulford,  A.  C.    Boundaries  and  Landmarks i2mo,  *t  oo 

Mullin,  J.  P.    Modern  Moulding  and  Pattern-making i2mo,  2  50 

Munby,  A.  E.     Chemistry  and  Physics  of  Building  Materials.     (West- 
minster Series.) 8vo,  *2  oo 

Murphy,  J.  G.    Practical  Mining i6mo,  i  oo 

Murphy.  W.  S.     Textile  Industries.     Eight  Volumes *2O  oo 

Murray,  J.  A.     Soils  and  Manures.     (Westminster  Series.) 8vo,  *2  oo 

Naquet,  A.    Legal  Chemistry I2mo,  2  oo 

Nasmith,  J.     The  Student's  Cotton  Spinning 8vo,  3  oo 

—  Recent  Cotton  Mill  Construction i2mo,  2  oo 

Neave,  G.  B.,  and  Heilbron,  I.  M.    Identification  of  Organic  Compounds. 

i2mo,  *i  25 

Neilson,  R.  M.    Aeroplane  Patents 8vo,  *2  oo 

Nerz,  F.     Searchlights.     Trans,  by  C.  Rodgers 8vo,  *3  oo 

Nesbit,  A.    F.     Electricity    and    Magnetism (In  Preparation.) 

Neuberger,  H.,  and  Noalhat,  H.     Technology  of  Petroleum.     Trans,  by 

J.  G.  Mclntosh 8vo,  *io  oo 

Newall,  J.  W.    Drawing,  Sizing  and  Cutting  Bevel-gears 8vo,  i  50 

Nicol,  G.     Ship  Construction  and  Calculations 8vo,  *4  50 

Nipher,  F.  E.    Theory  of  Magnetic  Measurements i2mo,  i  oo 

Nisbet,  H.     Grammar  of  Textile  Design 8vo,  *3  oo 

Nolan,  H.     The  Telescope.     (Science  Series  No.  51.) i6mo,  o  50 

Noll,  A.     How  to  Wire  Buildings i2mo,  i  50 

North,  H   B.    Laboratory  Experiments  in  General  Chemistry i2mo,  *i  oo 

Nugent,  E.     Treatise  on  Optics i2mo,  i  5r 

O'Connor,  H.     The  Gas  Engineer's  Pocketbook i2mo,  leather,  3  50 

—  Petrol  Air  Gas i2mo,  *o  75 

Ohm,  G.  S.,  and  Lockwood,  T.  D.     Galvanic  Circuit.     Translated  by 

William  Francis.  (Science  Series  No.  102.) i6mo,  o  50 

Olsen,  J.  C.  Text -book  of  Quantitative  Chemical  Analysis 8vo,  *4  QJ 

Olsson,  A.  Motor  Control,  in  Turret  Turning  and  Gun  Elevating.  (U.  S. 

Navy  Electrical  Series,  No.  i.) i2mo,  paper,  *o  50 

Oudin,  M.  A.  Standard  Polyphase  Apparatus  and  Systems 8vo,  *3  oo 

Pakes,  W,  C.  C.,  and  Nankivell,  A.  T.     The  Science  of  Hygiene  .  .8vo,  *i  75 

Palaz,  A.    Industrial  Photometry.     Trans,  by  G.  W.  Patterson,  Jr ..  8vo,  *4  oo 

Pamely,  C.     Colliery  Manager's  Handbook 8vo,  *io  oo 


20      D.   VAfl    NOSTRANU   COMPANY'S  SHORT  TITLE  CATALOG 

Parker,  P.  A.  M.     The  Control  of  Water 8vo  (In  Press.) 

Parr,  G.  D.  A.     Electrical  Engineering  Measuring  Instruments  ....  8vo,  *  3  50 

Parry,  E.  J.     Chemistry  of  Essential  Oils  and  Artificial  Perfumes. .  .8vo,  *s  oo 

Foods  and  Drugs.    Two  Volumes 8vo, 

Vol.   I.    Chemical  and  Microscopical  Analysis  of  Foods  and  Drugs.  *7  50 

Vol.  n.    Sale  of  Food  and  Drugs  Act *3  oo 

Parry,  E.  J.,  and  Coste,  J.  H.     Chemistry  of  Pigments 8vo,  *4  50 

Parry,  L.  A.     Risk  and  Dangers  of  Various  Occupations 8vo,  *3  oo 

Parshall,  H.  F.,  and  Hobart,  H.  M.     Armature  Windings 4to,  *7  50 

Electric  Railway  Engineering 4to,  *io  oo 

Parshall,  H.  F.,  and  Parry,  E.     Electrical  Equipment  of  Tramways. .  .  .  (In  Press.) 

Parsons,  S.  J.     Malleable  Cast  Iron 8vo,  *2  50 

Partington,  J.  R.    Higher  Mathematics  for  Chemical  Students.  .i2mo,  *2  oo 

—  Textbook  of  Thermodynamics 8vo  (In  Press.) 

Passmore,  A.  C.     Technical  Terms  Used  in  Architecture 8  ;o,  *3  50 

Patchell,  W.  H.    Electric  Power  in  Mines 8vo,  *4  oo 

Paterson,  G,  W.  L.    Wiring  Calculations i2mo,  *2  oo 

Patterson,  D.     The  Color  Printing  of  Carpet  Yarns 8vo,  *3  50 

Color  Matching  on  Textiles 8vo,  *3  oo 

The  Science  of  Color  Mixing 8v-o,  *3  oo 

Paulding,  0.  P.     Condensation  of  Steam  in  Covered  and  Bare  Pipes  .8vo,  *2  oo 

Transmission  of  Heat  through  Cold-storage  Insulation i2mo,  *i  oo 

Payne,  D.  W.    Iron  Founders'  Handbook (In  Press.) 

Peddie,  R.  A.    Engineering  and  Metallurgical  Books iimo,  *i  50 

Peirce,  B.     System  of  Analytic  Mechanics .  -4to,  10  oo 

Pendred,  V.     The  Railway  Locomotive.     (Westminster  Series.) 8vo,  *2  oo 

PerkK,  F.  M.     Practical  Methods  of  Inorganic  Chemistry i2mo,  *i  oo 

Perrigo,  O.  E.     Change  Gear  Devices 8vo,  i  oo 

Perrine,  F.  A.  C.     Conductors  for  Electrical  Distribution .8vo,  *3  50 

Perry,  J.     Applied  Mechanics 8vo,  *2  50 

Petit,  G.     White  Lead  and  Zinc  White  Paints 8vo,  *i  50 

Petit,  R.     How  to  Build  an  Aeroplane.     Trans,  by  T.  O'B.  Hubbard,  and 

J.  H.  Ledeboer 8vo,  *i  50 

Pettit,  Lieut.  J.  S.     Graphic  Processes.     (Science  Series  No.  76.) . . .  i6mo,  o  50 
Philbrick,  P.  H.     Beams  and  Girders.     (Science  Series  No.  88.) . . .  i6mo, 

Phillips,  J.     Engineering  Chemistry 8vo,  *4  50 

Gold  Assaying 8 vo,  *2  50 

- —  Dangerous  Goods 8vo,  3  50 

Phin,  J.     Seven  Follies  of  Science i2mo,  *i  25 

Pickworth,  C.  N.     The  Indicator  Handbook.     Two  Volumes.  .  i2mo,  each,  i  50 

Logarithms  for  Beginners I2mo-  boards,  o  50 

The  Slide  Rule i2mo,  i  oo 

Plattner's  Manual  of  Blow-pipe  Analysis.    Eighth  Edition,  revised.    Trans. 

by  H.  B.  Cornwall 8vo,  *4  oc 

Plympton,  G.  W.    The  Aneroid  Barometer.    (Science  Series  No.  35.)   i6mo,  o  50 

How  to  become  an  Engineer.      (Science  Series  No.  100.) i6mo,  o  50 

Van  Nostrand's  Table  Book.     (Science  Series  No.  104.) i6mo,  o  50 

Pochet,  M.  L.     Steam  Injectors,     Translated  from  the  French.     (Science 

Series  No.  29.) i6mo,  o  50 

Pocket  Logarithms  to  Four  Places.     (Science  Series  No.  65.) i6mo,  o  50 

leather,  i  oo 


D.   VAN    NOSTRAND   COMPANY'S  SHORT  TITLE   CATALOG      21 

Polleyn,  F      Dressings  and  Finishings  for  Textile  Fabrics 8vo,  *3  oo 

Pope,  F.  G.     Organic  Chemistry i2mo,  *2  25 

Pope,  F.  L.     Modern  Practice  of  the  Electric  Telegraph 8vo,  i  50 

Popplewell,  W.  C.  Elementary  Treatise  on  Heat  and  Heat  Engines.  .  i2mo,  *3  oo 

—  Prevention  of  Smoke 8vo,  *3  50 

—  Strength  of  Materials 8vo,  *i  75 

Porter,  J.  R.    Helicopter  Flying  Machine i2mo,  *i  25 

Potter,  T.     Concrete 8vo,  *3  oo 

Potts,  H.  E.     Chemistry  of  the  Rubber  Industry.     (Outlines  of  Indus- 
trial Chemistry) 8vo,  *2  oo 

Practical  Compounding  of  Oils,  Tallow  and  Grease 8vo,  *3  50 

Practical  Iron  Founding i2mo,  i  50 

Pratt,  K.    Boiler  Draught i2mo,  *i  2$ 

Pray,  T.,  Jr.     Twenty  Years  with  the  Indicator 8vo,  2  50 

—  Steam  Tables  and  Engine  Constant 8vo,  2  oo 

—  Calorimeter  Tables 8vo,  i  oo 

Preece,  W.  H.     Electric  Lamps (In  Press.) 

Prelini,  C.     Earth  and  Rock  Excavation 8vo,  *3  oo 

—  Graphical  Determination  of  Earth  Slopes 8vo,  *2  oo 

—  Tunneling.    New  Edition 8vo,  *3  oo 

—  Dredging.    A  Practical  Treatise 8vo,  *3  oo 

Prescott,  A.  B.     Organic  Analysis 8vo,  5  co 

Prescott,  A.  B.,  and  Johnson,  0.  C.     Qualitative  Chemical  Analysis. .  .8vo,  *3  50 
Prescott,  A.  B.,  and  Sullivan,  E.  C.     First  Book  in  Qualitative  Chemistry. 

i2mo,  *i  50 

Prideaux,  E.  B.  R.    Problems  in  Physical  Chemistry 8vo,  *2  oo 

Pritchard,  O.  G.     The  Manufacture  of  Electric-light  Carbons .  .  8vo,  paper,  *o  60 
Pullen,  W.  W.  F.     Application  of  Graphic  Methods  to  the  Design  of 

Structures i2mo,  *2  50 

—  Injectors:  Theory,  Construction  and  Working i2mo,  *i  50 

Pulsifer,  W.  H.     Notes  for  a  History  of  Lead 8vo,  4  oo 

Purchase,  W.  R.     Masonry i2mo,  *3  oo 

Putsch,  A.     Gas  and  Coal-dust  Firing 8vo,  *3  oo 

Pynchon,  T.  R.     Introduction  to  Chemical  Physics 8vo,  3  oo 

Rafter  G.  W.     Mechanics  of  Ventilation.     (Science  Series  No.  33.) .  i6mo,  o  50 

—  Potable  Water,     (Science  Series  No.  103.) i6mc  50 

Treatment  of  Septic  Sewage.     (Science  Series  No.  118.). . . .  i6mo  50 

Rafter,  G.  W.,  and  Baker,  M.  N.     Sewage  Disposal  in  the  United  States. 

4to,  *6  oo 

Raikes,  H.  P.     Sewage  Disposal  Works 8vo,  *4  oo 

Railway  Shop  Up-to-Date 4to,  2  oo 

Ramp,  H.  M.     Foundry  Practice (In  Press.) 

Randall,  P.  M.     Quartz  Operator's  Handbook i2mo,  2  oo 

Randau,  P.     Enamels  and  Enamelling 8vo,  *4  oo 

Rankine,  W.  J.  M.     Applied  Mechanics 8vo,  5  oo 

—  Civil  Engineering 8vo,  6  50 

-  Machinery  and  Millwork 8vo,  5  jo 

— —  The  Steam-engine  and  Other  Prime  Movers 8vo,  5  oo 

-  Useful  Rules  and  Tables 8vo,  4.  oo 

Rankine,  W.  J.  M.,  and  Bamber,  E.  F.     A  Mechanical  Text-book 8vo,  3  50 


ZZ      D.   VAN    NOSTRAND   COMPANY'S   SHORT  TITLE  CATALOG 

Raphael,  F.  C.     Localization  of  Faults  in  Electric  Light  and  Power  Mains. 

8vo,  *3  oo 

Rasch,  E.     Electric  Arc  Phenomena.     Trars.  by  K.  Tornberg 8vo,  *2  c; 

Rathbone,  R.  L.  B.     Simple  Jewellery .  .8vo,  *2  oo 

Rateau,  A.     Flow  of  Steam  through  Nozzles  and  Orifices.     Trans,  by  H. 

B.  Brydon 8vo.  *i  50 

Rausenberger,  F.     The  Theory  of  the  Recoil  of  Guns 8vo,  *4  50 

Rautenstrauch,  W.    Notes  on  the  Elements  of  Machine  Design. 8 vo,  boards,  *i  sc 
Rautenstrauch,  W.,  and  Williams,  J.  T.     Machine  Drafting  and  Empirical 

Design. 

Part   I.  Machine  Drafting 8vo,  *i  25 

Part  II.  Empirical  Design (In  Preparation.) 

Raymond,  E.  B.     Alternating  Current  Engineering i2mo,  *2  50 

Rayner,  H.     Silk  Throwing  and  Waste  Silk  Spinning 8vo,  *2  50 

Recipes  for  the  Color,  Paint,  Varnish,  Oil,  Soap  and  Drysaltery  Trades .  8vo,  *3  50 

Recipes  for  Flint  Glass  Making I2mo,  *4  50 

Redfern,  J.  B.,  and  Savin,  J.    Bells,  Telephones  (Installation  Manuals 

Series.) i6mo,  *o  50 

Redwood,  B.     Petroleum.     (Science  Series  No.  92.) i6mo,  o  50 

Reed,  S.    Turbines  Applied  to  Marine  Propulsion *5  oo 

Reed's  Engineers'  Handbook 8vo,  *s  oo 

Key  to  the  Nineteenth  Edition  of  Reed's  Engineers'  Handbook . .  8vo,  *3  oo 

Useful  Hints  to  Sea-going  Engineers i2mo,  i  50 

Marine  Boilers i2mo,  2  oo 

Guide  to  the  Use  of  the  Slide  Valve i2mo,  *i  60 

Reinhardt,  C.  W.     Lettering  for  Draftsmen,  Engineers,  and  Students. 

oblong  4to,  boards,  i  oo 

The  Technic  of  Mechanical  Drafting oblong  4to,  boards,  *i  oo 

Reiser,  F.     Hardening  and  Tempering  of  Steel.     Trans,  by  A.  Morris  and 

H.  Robson i2mo,  *2  50 

Reiser,  N.     Faults  in  the  Manufacture  of  Woolen  Goods.     Trans,  by  A. 

Morris  and  H.  Robson ; 8vo,  *2  50 

Spinning  and  Weaving  Calculations 8vo,  *5  oo 

Renwick,  W.  G.     Marble  and  Marble  Working 8vo,  5  oo 

Reynolds,   0.,  and  Idell,   F.   E.     Triple  Expansion  Engines.     (Science 

Series  No.  99.) i6mo,  o  50 

Rhead,  G.  F.     Simple  Structural  Woodwork 12 mo,  *i  oo 

Rice,  J.  M.,  and  Johnson,  W.  W.     A  New  Method  of  Obtaining  the  Differ- 
ential of  "^unctions i2mo,  o  50 

Richards,  W.  A.,  and  North,  H.  B.    Manual  of  Cement  Testing i2mo,  *i  50 

Richardson,  J.     The  Modern  Steam  Engine 8vo,  *3  50 

Richardson,  S.  S.     Magnetism  and  Electricity i2mo,  *2  oo 

Rideal,  S.     Glue  and  Glue  Testing 8vo,  *4  oo 

Rimmer,  E.  J.    Boiler  Explosions,  Collapses  and  Mishaps 8vo,  *i  75 

Rings,  F.     Concrete  in  Theory  and  Practice i2mo,  *2  50 

Reinforced  Concrete  Bridges 4to,  *$  oo 

Ripper,  W.     Course  of  Instruction  in  Machine  Drawing folio,  *6  oo 

Roberts,  F.  C.    Figure  of  the  Earth.     (Science  Series  No.  79.) i6mo,  o  50 

Roberts,  J  ,  Jr.     Laboratory  Work  in  Electrical  Engineering 8vo,  *2  oo 

Robertson,  L.  S.     Water-tube  Boilers 8vo,  2  oo 

Robinson,  J.  B.     Architectural  Composition 8vo,  *2  50 


D.  VAN  NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG     23 

Robinson,  S.  W.     Practical  Treatise  on  the  Teeth  of  Wheels.     (Science 

Series  No.  24.) i6mo,  o  50 

—  Railroad  Economics.     (Science  Series  No.  59.) i6mo,  o  50 

-  Wrought  Iron  Bridge  Members.     (Science  Series  No.  60.) i6mo,  050 

Robson,  J.  H.     Machine  Drawing  and  Sketching 8vo,  *i  50 

Roebling,  J  A.     Long  and  Short  Span  Railway  Bridges folio,  25  oo 

Rogers,  A.     A  Laboratory  Guide  of  Industrial  Chemistry i2mo,  *i  50 

Rogers,  A.,  and  Aubert,  A.  B.     Industrial  Chemistry 8vo,  *5  oo 

Rogers,  F.     Magnetism  of  Iron  Vessels.     (Science  Series  No.  30.) .  i6mo,  o  50 
Rohland,  P.     Colloidal  and  Crystalloidal  State  of  Matter.     Trans,  by 

W.  J.  Britland  and  H.  E.  Potts I2mo,  *i  25 

Rollins,  W.     Notes  on  X-Light 8vo,  *s  oo 

Rollinson,  C.     Alphabets Oblong,  i2mo,  *i  oo 

Rose,  J.     The  Pattern-makers'  Assistant 8vo,  2  50 

—  Key  to  Engines  and  Engine-running I2mo,  2  50 

Rose,  T.  K.     The  Precious  Metals.     (Westminster  Series.) 8vo,  *2  oo 

Rosenhain,  W.     Glass  Manufacture.     (Westminster  Series.) 8vo,  *2  oo 

Xoss,  W.  A.     Blowpipe  in  Chemistry  and  Metallurgy I2mo,  *2  oo 

Rossiter,  J.  T.    Steam  Engines.    (Westminster  Series.) .  .8vo  (In  Press.) 

—  Pumps  and  Pumping  Machinery.     (Westminster  Series.) ....  .8vo, 

(In  Press.) 

Roth.     Physical  Chemistry 8vo,  *2  oo 

Rouillion,  L.     The  Economics  of  Manual  Training 8vo,  2  oo 

Rowan,  F.  J.     Practical  Physics  of  the  Modern  Steam-boiler 8vo,  *3  oo 

Rowan,  F.  J.,   and  Idell,  F.   E.     Boiler  Incrustation  and   Corrosion. 

(Science  Series  No.  27.) i6mo,  o  50 

Roxburgh,  W.     General  Foundry  Practice 8vo,  *3  50 

Ruhmer,  E.     Wireless  Telephony.     Trans,  by  J.  Erskme-Murray .  .  8vo,  *3  50 

Russell,  A.     Theory  of  Electric  Cables  and  Networks 8vo,  *3  oo 

Sabine,  R.     History  and  Progress  of  the  Electric  Telegraph i2mo,  i  25 

Saeltzer,  A.     Treatise  on  Acoustics i2mo,  i  oo 

Salomons,  D.     Electric  Light  Installations.     i2mo. 

Vol.     I.     The  Management  of  Accumulators 2  50 

Vol.    II.     Apparatus 2  25 

Vol.  III.     Applications i  50 

Sanford,  P.  G.     Nitro-explosives 8vo,  *4  oo 

Saunders,  C.  H.     Handbook  of  Practical  Mechanics i6mo,  i  oo 

leather,  i  25 

Saunnier,    C.     Watchmaker's   Handbook i2mo,  3  oo 

Sayers,  H.  M.     Brakes  for  Tram  Cars 8vo,  *i  25 

Scheele,  C.  W.     Chemical  Essays 8vo,  *2  oo 

Scheithauer,    W.     Shale    Oils    and    Tars 8vo,  *3  50 

Schellen,  H.     Magneto-electric  and  Dynamo-electric  Machines  ....  8vo,  5  oo 

Scherer,  R.     Casein.     Trans,  by  C.  Salter 8vo,  *3  oo 

Schidrowitz,  P.     Rubber,  Its  Production  and  Industrial  Uses 8vo,  *5  oo 

Schindler,  K.     Iron  and  Steel  Construction  Works i2mo,  *i  25 

Schmall,  C.  N.     First  Course  in  Analytic  Geometry,  Plane  and  Solid. 

i2mo,  hah*  leather,  *i  75 

Schmall,  C.  N.,  and  Shack,  S.  M.     Elements  of  Plane  Geometry. . .  i2mo,  *i  25 

Schmeer,  L.     Flow  of  Water 8vo,  *3  oo 


24     D.  VAN  'NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG 

Schumann,  F.     A  Manual  of  Heating  and  Ventilation ....  i2mo,  leather,  i  50 

Schwarz,  E.  H.  L.     Causal  Geology 8vo,  *2  50 

Schweizer,  V.     Distillation  of  Resins 8vo,  *3  50 

Scott,  W.  W.     Qualitative  Analysis.     A  Laboratory  Manual 8vo,  *i  50 

Scribner,  J.  M.     Engineers' and  Mechanics' Companion..  .i6mo,  leather,  i  50 

Searle,  A.  B.     Modern  Brickmaking 8vo,  *5  oo 

Searle,    G.    M.     "  Sumners'    Method."      Condensed    and    Improved. 

(Science  Series  No.  124.) i6mo,  o  50 

Seaton,  A.  E.     Manual  of  Marine  Engineering 8vo,  8  oo 

Seaton,  A.  E.,  and  Rounthwaite,  H.  M.    Pocket-book  of  Marine  Engineer- 
ing   i6mo,  leather,  3  oo 

Seeligmann,  T.,  Torrilhon,  G.  L.,  and  Falconnet,  H.     India  Rubber  and 

Gutta  Percha.     Trans,  by  J.  G.  Mclntosh 8vo,  *s  oo 

Seidell,  A.     Solubilities  of  Inorganic  and  Organic  Substances 8vo,  *3  oo 

Sellew,  W.  H.     Steel  Rails 4to,  *i2  50 

Senter,  G.     Outlines  of  Physical  Chemistry i2mo,  *i  75 

-  Text-book  of  Inorganic  Chemistry i2mo,  *i  75 

Sever,  G.  F.     Electric  Egnineering  Experiments 8vo,  boards,  *i  oo 

Sever,  G.  F.,  and  Townsend,  F.     Laboratory  and  Factory  Tests  in  Elec- 
trical Engineering 8vo,  *2  50 

Sewall,  C.  H.    Wireless  Telegraphy 8vo,  *2  oo 

—  Lessons  in  Telegraphy i2mo,  *i  oo 

Sewell,  T.     Elements  of  Electrical  Engineering 8vo,  *3  oo 

—  The  Construction  of  Dynamos 8vo,  *3  oo 

Sexton,  A.  H.     Fuel  and  Refractory  Materials i2mo,  *2  50 

—  Chemistry  of  the  Materials  of  Engineering i2mo,  *2  50 

Alloys  (Non-Ferrous) 8vo,  *3  oo 

—  The  Metallurgy  of  Iron  and  Steel 8vo,  *6  50 

Seymour,  A.     Practical  Lithography 8vo,  *2  50 

Modern  Printing  Inks 8vo,  *2  oo 

Shaw,  Henry  S.  H.     Mechanical  Integrators.     (Science  Series  No.  83.) 

i6mo,  o  50 

Shaw,  P.  E.     Course  of  Practical  Magnetism  and  Electricity 8vo,  *i  oo 

Shaw,  S.     History  of  the  Staffordshire  Potteries 8vo,  2  oo 

—  Chemistry  of  Compounds  Used  in  Porcelain  Manufacture  ....  8vo,  *5  oo 

Shaw,  W.  N.     Forecasting  Weather 8vo,  *3  50 

Sheldon,  S.,  and  Hausmann,  E.     Direct  Current  Machines i2mo,  *2  50 

—  Alternating  Current  Machines i2mo,  *2  50 

Sheldon,  S.,  and  Hausmann,  E.      Electric  Traction  and  Transmission 

Engineering i2mo,  *2  50 

Sheriff,  F.  F.     Oil  Merchants'  Manual i2mo,  *3  50 

Shields,  J.  E.     Notes  on  Engineering  Construction i2mo,  i  50 

Shreve,  S.  H.     Strength  of  Bridges  and  Roofs 8vo,  3  50 

Shunk,  W.  F.     The  Field  Engineer izmo,  morocco,  2  50 

Simmons,  W.  H.,  and  Appleton,  H.  A.     Handbook  of  Soap  Manufacture. 

8vo,  *3  oo 

Simmons,  W.  H.,  and  Mitchell,  C.  A.     Edible  Fats  and  Oils 8vo,  *  3  oo 

Simms,  F.  W.     The  Principles  and  Practice  of  Levelling 8vo,  2  50 

—  Practical  Tunneling 8vo,  7  50 

Simpson,  G.     The  Naval  Cnostructor i2mo,  morroco,  *5  oo 

Simpson,  W.     Foundations 8vo  (In  Press.} 


D.  VAN  NOSTBAND  COMPANY'S  SHORT  TITLE  CATALOG     25 

Sinclair,  A.     Development  of  the  Locomotive  Engine..  .8vo,  half  leather,  5  o  , 

—  Twentieth  Century  Locomotive 8vo,  half  leather,  *  5  oo 

Sindall,  R.  W.,  and  Bacon,  W.  N.     The  Testing  of  Wood  Pulp 8vo,  *2  50 

Sindall,  R.  W.     Manufacture  of  Paper.     (Wesmtinster  Series.) .  .  .  .8vo,  *2  OD 

Sloane,  T.  O'C.     Elementary  Electrical  Calculations i2mo,  *2  oo 

Smith,  C.  A.  M.     Handbook  of  Testing,  MATERIALS 8vo,  *2  50 

.Smith,  C.  A.  M.,  and  Warren,  A.  G.     New  Steam  Tables 8vo,  *i  25 

:Smith,  C.  F.     Practical  Alternating  Currents  and  Testing 8vo,  *2  50 

—  Practical  Testing  of  Dynamos  and  Motors 8vo,  *2  oo 

Smith,  F.  E.     Handbook  of  General  Instruction  for  Mechanics.  .  .I2mo,  i  50 

Smith,  J.  C.     Manufacture  of  Paint 8vo,  *3  oo 

—  Paint  and  Painting  Defects 

Smith,  R.  H.     Principles  of  Machine  Work i2mo,  *3  oo 

—  Elements  of  Machine  Work i2mo,  *2  oo 

Smith,  W.     Chemistry  of  Hat  Manufacturing 121110,  *3  oo 

Snell,    A.    T.     Electric    Motive  Power 8vo,  *4  eo 

Snow,  W.  G.     Pocketbook  of  Steam  Heating  and  Ventilation.    (In  Press.) 
Snow,  W.  G.,  and  Nolan,  T.     Ventilation  of  Buildings.     (Science  Series 

No.  5.) i6mo.  o  50 

Soddy,  F.     Radioactivity 8vo,  *3  oo 

Solomon,  M.     Electric  Lamps.     (Westminster  Series.) 8vo,  *2  oo 

Sothern,  J.  W.     The  Marine  Steam  Turbine 8vo,  *5  eo 

Southcombe,  J.  E.     Chemistry  of  the  Oil  Industries.     (Outlines  of  In- 
dustrial Chemistry.) 8vo,  *3  oo 

Soxhlet,  D.  H.     Dyeing  and  Staining  Marble.     Trans,  by  A.  Morris  and 

H.  Robson 8vo,  *2  50 

Spang,  H.  W.     A  Practical  Treatise  on  Lightning  Protection i2mo,  i  OD 

Spangenburg.  L.     Fatigue  of  Metals.     Translated  by  S.  H.   Shreve. 

(Science  Series  No.  23.) i6mo,  o  50 

Specht,  G.  J.,  Hardy,  A.  S.,  McMaster,  J.  B.,  and  Walling.    Topographical 

Surveying.     (Science  Series  No.  72.) i6mo,  o  50 

Speyers,  C.  L.     Text-book  of  Physical  Chemistry 8vo,  *2  25 

Stahl,  A.  W.     Transmission  of  Power.     (Science  Series  No.  28.)  .  i6mo, 

Stahl,  A.  W.,  and  Woods,  A.  T.     Elementary  Mechanism i2mo,  *2  oo 

Staley,  C.,  and  Pierson,  G.  S.     The  Separate  System  of  Sewerage. .  .8vo,  *3  oo 

Standage,  H.  C.     Leatherworkers'  Manual 8vo,  *3  50 

—  Sealing  Waxes,  Wafers,  and  Other  Adhesives 8vo,  *2  oo 

—  Agglutinants  of  all  Kinds  for  all  Purposes i2mo,  *3  50 

Stansbie,  J.  H.     Iron  and  Steel.     (Westminster  Series.) 8vo,  *2  oo 

Steadman,  F.  M.     Unit  Photography  and  Actinometry (In  Press.) 

Steinman,  D.  B.     Suspension  Bridges  and  Cantilevers.     (Science  Series 

No.  127.) o  50 

Stevens,  H.  P.     Paper  Mill  Chemist i6mo,  *2  50 

Stevenson,  J.  L.     Blast-Furnace  Calculations i2mo,  leather,  *2  oo 

Stewart,  A.     Modern  Polyphase  Machinery i2mo,  *2  oo 

Stewart,  G.     Modern  Steam  Traps i2mo,  *i  25 

Stiles,  A.     Tables  for  Field  Engineers i2mo,  i  oo 

Stillman,  P.     Steam-engine  Indicator i2mo,  i  oo 

Stodola,  A.     Steam  Turbines.     Trans,  by  L.  C.  Loewenstein 8vo,  *5  oo 

Stone,  H.     The  Timbers  of  Commerce 8vo,  3  50 

Stone,  Gen.  R.     New  Roads  and  Road  Laws i2mo,  i  oo 


26      D.  VAN  NOSTKAND  COMPANY'S  SHORT  TITLE  CATALOG 

Stopes,  M.    Ancient  Plants 8vo,  *2  oo 

-  The  Study  of  Plant  Life 8vo,  *2  oo 

Stumpf,  Prof.     Una-Flow  of  Steam  Engine 4to,  *3  50 

Sudborough,  J.  J.,  and  James,  T.  C.    Practical  Organic  Chemistry..  i2mo,  *2  oo 

Suffling,  E.  R.     Treatise  on  the  Art  of  Glass  Painting 8vo,  *3  50 

Suggate,  A.     Elements  of  Engineering  Estimating i2mo,  *i  50 

Swan,  K.     Patents,  Designs  and  Trade  Marks.     (Westminster  Series.). 

8vo,  *2  oo 

Sweet,  S.  H.     Special  Report  on  Coal 8vo,  3  oo 

Swinburne,  J.,  Wordingham,  C.  H.,  and  Martin,  T.  C.     Electric  Currents. 

(Science  Series  No.  109.) , i6mo,  o  50 

Swoope,  C.  W.    Lessons  in  Practical  Electricity i2mo,  *2  oo 

Tailf er,  L.    Bleaching  Linen  and  Cotton  Yarn  and  Fabrics 8vo,  *5  oo 

Tate,  J.  S.     Surcharged  and  Different  Forms  of  Retaining- walls.    (Science 

Series  No.  7.) i6mo,  o  50 

Taylor,  E.  N.     Small  Water  Supplies i2mo,  *2  oo 

Templeton,  W.     Practical  Mechanic's  Workshop  Companion. 

i2mo,  morocco,  2  oo 
Terry,  H.  L.     India  Rubber  and  its  Manufacture.     (Westminster  Series.) 

8vo,  *2  oo 
Thayer,  H.  R.     Structural  Design.     8vo. 

Vol.     I.    Elements  of  Structural  Design *2  oo 

Vol.    II.     Design  of  Simple  Structures (In  Preparation.) 

Vol.  III.    Design  of  Advanced  Structures (In  Preparation.) 

Thiess,  J.  B.,  and  Joy,  G.  A.     Toll  Telephone  Practice 8vo,  *3  50 

Thorn,  C.,  and  Jones,  W.  H.     Telegraphic  Connections.. .  .oblong,  i2mo,  i  50 

Thomas,  C.  W.     Paper-makers'  Handbook (In  Press.} 

Thompson,  A.  B.     Oil  Fields  of  Russia 4to,  *y  50 

Petroleum  Mining  and  Oil  Field  Development 8vo,  *5  oo 

Thompson,  S.  P.     Dynamo  Electric  Machines.     (Science  Series  No.  75.) 

i6mo,  o  50 

Thompson,  W.  P.     Handbook  of  Patent  Law  of  All  Countries i6mo,  i  50 

Thomson,  G.  S.     Milk  and  Cream  Testing i2mo,  *i  75 

Modern  Sanitary  Engineering,  House  Drainage,  etc 8vo,  *3  oo 

Thornley,  T.     Cotton  Combing  Machines 8vo,  *3  oo 

Cotton  Waste 8vo,  *3  oo 

Cotton  Spinning.     8vo. 

First  Year *i  50 

Second   Year *2  50 

Third  Year *2  50 

Thurso,  J.  W.     Modern  Turbine  Practice 8vo,  *4  oo 

Tidy,  C.  Meymott.     Treatment  of  Sewage.     (Science  Series  No.  94.) i6mo,  o  50 
Tillmans,   J.     Water   Purification   and   Sewage   Disposal.     Trans,   by 

Hugh  S.  Taylor 8vo,  *2  oo 

Tinney,  W.  H.     Gold-mining  Machinery 8vo,  *3  oo 

Titherley,  A.  W.     Laboratory  Course  of  Organic  Chemistry 8vo,  *2  oo 

Toch,  M.     Chemistry  and  Technology  of  Mixed  Paints 8vo,  *3  oo 

—  Materials  for  Permanent  Painting i2mo,  *2  oo 

Todd,  J.,  and  Whall,  W.  B.    Practical  Seamanship 8vo,  *7  50 

Tonge,  J.     Coal      (Westminster  Series.) 8vo,  *2  oo 


D.  VAN  NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG      - 

Townsend,  F.     Alternating  Current  Engineering 8vo,  boards,  *o  75 

Townsend,  J.     lonization  of  Gases  by  Collision 8vo,  *i  25 

Transactions  of  the  American  Institute  of  Chemical  Engineers,     8vo. 

Vol.     I.     1908 *6  oo 

Vol.   II.     1909 *6  oo 

Vol.  III.     1910 *6  oo 

Vol.  IV.     1911 *6  oo 

Vol.    V.     1912 *6  oo 

Traverse  Tables.     (Science  Series  No.  115.) i6mo,  o  50 

morocco,  i  oo 
Trinks,  W.,  and  Housum,  C.     Shaft  Governors.     (Science  Series  No.  122.) 

i6mo,  o  50 

Trowbridge,  W.  P.     Turbine  Wheels.     (Science  Series  No.  44.) .  .  i6mo,  o  50 

Tucker,  J.  H.     A  Manual  of  Sugar  Analysis 8vo,  3  50 

Tunner,  P.  A.     Treatise  on  Roll-turning.     Trans,  by  J.  B.  Pearse. 

8vo,  text  and  folio  atlas,  10  oo 
Turnbull,  Jr.,  J.,  and  Robinson,  S.  W.     A  Treatise  on  the  Compound 

Steam-engine.     (Science  Series  No.  8.) i6mo, 

Turrill,  S.  M.     Elementary  Course  in  Perspective i2mo,  *i  25 

Underbill,  C.  R.     Solenoids,  Electromagnets  and  Electromagnetic  Wind- 
ings   i2mo,  *2  oo 

Urquhart,  J.  W.     Electric  Light  Fitting i*2mo,  2  oo 

—  Electro-plating i2mo,  2  oo 

—  Electrotyping i2mo,  2  oo 

—  Electric  Ship  Lighting i2mo,  3  oo 

Usborne,  P.  O.  G.     Design  of  Simple  Steel  Bridges 8vo,  *4  oo 

Vacher,  F.    Food  Inspector's  Handbook i2mo,  *2  50 

Van  Nostrand's  Chemical  Annual.    Third  issue  1913.  ..  .leather,  lamo,  *2  50 

—  Year  Book  of  Mechanical  Engineering  Data.   First  issue  1912 ....  (In  Press.) 

Van  Wagenen,  T.  F.     Manual  of  Hydraulic  Mining i6mo,  i  oo 

Vega,  Baron  Von.     Logarithmic  Tables 8vo,  cloth,  2  oo 

half  morroco,  2  50 
Villon,  A.  M.  Practical  Treatise  on  the  Leather  Industry.  Trans,  by 

F.  T.  Addyman 8vo,  *io  oo 

Vincent,  C.  Ammonia  and  its  Compounds.  Trans,  by  M.  J.  Salter .  8vo,  *2  oo 

Volk,  C.  Haulage  and  Winding  Appliances §vo,  *4  Oo 

Von  Georgievics,  G.  Chemical  Technology  of  Textile  Fibres.  Trans. 

by  C.  Salter 8vo,  *4  50 

—  Chemistry  of  Dyestuffs.     Trans,  by  C.  Salter 8vo,  *4  50 

Vose,  G.  L.     Graphic  Method  for  Solving  Certain  Questions  in  Arithmetic 

and  Algebra      (Science  Series  No.  16.) i6mo,  o  50 

Wabner,  R.     Ventilation  in  Mines.     Trans,  by  C.  Salter 8vo,  *4  50 

Wade,  E.  J.     Secondary  Batteries 8vo,  *4  oo 

Wadmore,  T.  M.     Elementary  Chemical  Theory i2mo,  *i  50 

Wadsworth,  C.     Primary  Battery  Ignition i2mo,  *o  50 

Wagner,  E.     Preserving  Fruits,  Vegetables,  and  Meat i2mo,  *2  50 

Waldram,  P.  J.     Principles  of  Structural  Mechanics i2mo,  *3  oo 

Walker,  F.     Aerial  Navigation 8vo,  2  oo 

—  Dynamo  Building.     (Science  Series  No.  98.) i6mo,  o  50 


28     D.  VAN    NOSTRAND  COMPANY'S  SHORT  TITLE  CATALOG 

Walksr,  F.     Electric  Lighting  for  Marine  Engineers 8vo,  2  oo 

Walker,  S.  F.     Steam  Boilers,  Engines  and  Turbines 8vo,  3  oo 

—  Refrigeration,  Heating  and  Ventilation  on  Shipboard i2mo,  *2  oo 

—  Electricity  in  Mining 8vo,  *3  50 

Wallis-Tayler,  A.  J.    Bearings  and  Lubrication 8vo,  *i  50 

—  Aerial  or  Wire  Ropeways 8vo,  *3  oo 

—  Motor  Cars 8vo,  i  80 

—  Motor  Vehicles  for  Business  Purposes 8vo,  3  50 

Wallis-Tayler,  A.  J.     Pocket  Book  of  Refrigeration  and  Ice  Making.  12010,  i  50 

Refrigeration,  Cold  Storage  and  Ice-Making 8vo,  *4  50 

Sugar  Machinery i2mo,  *2  oo 

Wanklyn,  J.  A.     Water  Analysis i2mo,  2  oo 

Wansbrough,  W.  D.     The  A  B  C  of  the  Differential  Calculus i2mo,  *i  50 

Slide  Valves i2mo,  *2  oo 

Ward,  J.  H.     Steam  for  the  Million 8vo,  i  oo 

Waring,  Jr.,  G.  E.     Sanitary  Conditions.     (Science  Series  No.  31.).  .i6mo,  050 

Sewerage  and  Land  Drainage *6  oo 

Waring,  Jr.,  G.  E.    Modern  Methods  of  Sewage  Disposal i2mo,  2  oo 

How  to  Drain  a  House i2mo,  i  25 

Warren,  F.  D.     Handbook  on  Reinforced  Concrete i2mo,  *2  50 

Watkins,  A.    Photography.     (Westminster  Series.) 8vo,  *2  oo 

Watson,  E.  P.     Small  Engines  and  Boilers 12010,  i  25 

Watt,  A.     Electro-plating  and  Electro-refining  of  Metals 8vo,  *4  50 

Electro-metallurgy i2mo,  i  oo 

• The  Art  of  Soap-making 8vo,  3  oo 

Leather  Manufacture 8vo,  *4  oo 

Paper-Making 8vo,  3  oo 

Weale,  J.     Dictionary  of  Terms  Used  in  Architecture 12 mo,  2  50 

Weale's  Scientific  and  Technical  Series.     (Complete  list  sent  on  applica- 
tion.) 

Weather  and  Weather  Instruments i2mo,  i  oo 

paper,  o  50 

Webb,  H.  L.     Guide  to  the  Testing  of  Insulated  Wires  and  Cables. .  i2mo,  i  oo 

Webber,  W.  H.  Y.     Town  Gas.     (Westminster  Series.) 8vo,  *2  oo 

Weisbach,  J.     A  Manual  of  Theoretical  Mechanics 8vo,  *6  oo 

sheep,  *7  50 

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